Glossary · 40 terms
AI, digital marketing and trades glossary
Citable definitions for AEO, GEO, LLM citability, AI receptionist and schema markup, tailored for the UK trades market.
AI, GEO and AEO11
AEO
Answer Engine Optimisation (AEO) is the discipline of structuring and formatting content so that AI tools such as ChatGPT, Perplexity, and Google AI Overviews select and cite it as a direct answer to a user query — without requiring any click on a search result. AEO complements classical SEO and prioritises authority, semantic structure, and citability over click-through ranking.
AI Mode Google
AI Mode is Google's advanced conversational search interface, launched in the United States in May 2025 at Google I/O. It operates via query fan-out: the system decomposes a user's query into multiple simultaneous sub-queries processed by Gemini 2.0, supports follow-up questions, and generates responses with deep reasoning. Its thematic search mechanism is documented in patent US20240329934A1.
AI Overviews
AI Overviews is the Google Search feature that generates automatic summaries at the top of search results using the Gemini model via retrieval-augmented generation (RAG) over indexed web pages. Launched in May 2024 as the replacement for the Search Generative Experience (SGE), it was available in more than 200 countries and 40 languages by May 2025, and occupies position zero of the SERP.
Citability
Citability is the degree to which a piece of content can be accurately quoted, paraphrased, or attributed by a large language model in a generated answer. High-citability content shares four characteristics: it states a clear, verifiable claim; it attributes that claim to an identifiable source; it is written in plain, precise prose that a model can reproduce without distortion; and it is accessible to web crawlers used by RAG pipelines. Citability is the content-side complement to Share of Voice AI: SOV-AI measures the outcome (how often a brand is cited), while citability describes the structural properties of content that make that outcome more likely.
E-E-A-T
E-E-A-T stands for Experience, Expertise, Authoritativeness, and Trustworthiness. It is the quality framework Google's human Search Quality Raters use to evaluate content, and it increasingly shapes how AI answer engines — including Google AI Overviews, Perplexity, and ChatGPT — decide which sources to cite. For UK tradesmen and home-services businesses, E-E-A-T is not a ranking factor in the direct algorithmic sense but a signal cluster: verified credentials, first-hand project evidence, structured author markup, and consistent NAP data collectively raise the trust score that determines whether a business is cited in AI-generated answers or suppressed in favour of a competitor.
Fan-out query
A fan-out query is a retrieval strategy in which a single user prompt is decomposed into multiple sub-queries that are issued in parallel to one or more information sources, with the results aggregated before the language model generates a final response. The pattern originates in distributed database design, where fan-out describes splitting a read operation across multiple shards. In the context of agentic AI and RAG systems, fan-out queries are used when a single query is unlikely to retrieve all the evidence needed to answer a complex, multi-faceted question. Google's AI Overviews pipeline and Perplexity's Pro Search mode both use variants of fan-out querying.
GEO
Generative Engine Optimisation (GEO) is the practice of optimising web content to increase its visibility and citation frequency in responses generated by AI-powered search engines. The foundational paper was published in November 2023 by Aggarwal et al. (Princeton/Allen Institute, arXiv:2311.09735) and presented at KDD 2024; it demonstrated visibility improvements of up to 40% by adding statistics, external citations, and an authoritative voice.
Hallucination (LLM)
Hallucination in a large language model (LLM) refers to the generation of output that is factually incorrect, fabricated, or unsupported by the model's training data or the context provided, yet stated with apparent confidence. The term was formalised in the NLP literature by Maynez et al. (ACL 2020) for abstractive summarisation and has since become the standard term for any LLM output that is unfaithful to verifiable facts. Hallucination rates vary significantly by task: retrieval-augmented generation pipelines reduce — but do not eliminate — hallucination by grounding responses in retrieved passages.
llms.txt
llms.txt is a plain-text file placed at a website's root that provides large language models with a structured, markdown-formatted index of a site's most important content. Proposed by Jeremy Howard in September 2024 as an emerging standard, it had been adopted by 844,000 sites by November 2025 according to BuiltWith — yet a 10-week experiment by Search Engine Land found no detectable crawling of the file by any of the four major AI engines.
RAG (Retrieval-Augmented Generation)
Retrieval-Augmented Generation (RAG) is an AI architecture in which a language model's response is grounded by dynamically retrieved documents rather than relying solely on information encoded in model weights during training. The pattern was formalised by Lewis et al. at Facebook AI Research (NeurIPS 2020). In a RAG pipeline, a user query is first used to retrieve a set of relevant passages from an external knowledge source — a vector database, a search index, or a live web crawl — which are then prepended to the model's context window before generation. RAG is the dominant architecture behind Perplexity, Bing Copilot, Google AI Overviews, and ChatGPT's web-browsing mode.
Share of Voice AI
Share of Voice AI (SOV-AI) measures the proportion of AI-generated answers — in tools such as ChatGPT, Perplexity, Google AI Overviews, and Bing Copilot — in which a specific brand is mentioned or recommended, relative to the total mentions across its competitive set. Unlike traditional SOV, which counts paid impressions or organic rankings, SOV-AI tracks citation frequency in conversational outputs. Brands with strong SOV-AI tend to have structured, authoritative content that language models can cite verbatim, corroborated by high-domain-authority backlink profiles and consistent entity presence across the web.
Home services and construction15
AI phone receptionist
An AI phone receptionist is a voice-AI system that answers inbound calls on behalf of a trade or home-services business, conducts a natural-language conversation with the caller, qualifies the lead (job type, postcode, urgency, budget), books appointments directly into the company calendar, and sends a confirmation by SMS — without human intervention. Unlike an IVR (touch-tone menu) or a voicemail service, a modern AI receptionist handles open-ended questions, manages call interruptions, and adapts its script based on caller responses. For UK tradesmen, where a significant share of inbound calls go unanswered during working hours, AI phone receptionists directly convert missed calls into booked jobs.
Bark (UK)
Bark is a UK credit-based lead marketplace covering trades and professional services with no joining fee and no monthly subscription. Professionals register free of charge and purchase credits (standard price £1.80 excl. VAT per credit) to contact customers whose requests match their service area and category. There is no vetting gate at registration; trust is built through the platform's review and profile system after first contact.
Checkatrade
Checkatrade is a UK subscription-based trade directory and lead platform that vets tradespeople through up to 12 pre-admission checks — covering ID, qualifications, insurance and credit history — and continues monitoring members via verified customer reviews. Homeowners search and contact vetted trades directly; tradespeople pay a fixed monthly membership fee (from £30 + VAT) to appear in postcode-targeted listings and receive a steady flow of inbound enquiries rather than paying per lead.
Customer Acquisition Cost for Tradesmen
Customer Acquisition Cost (CAC) for tradesmen is the total marketing and sales spend divided by the number of new customers gained in a given period. For UK trades businesses — plumbers, electricians, builders, gas engineers — CAC typically ranges from £80 to £300 depending on the acquisition channel (organic search, paid ads, referral networks, or directories such as Checkatrade). Reducing CAC without sacrificing lead quality is the primary lever for improving profitability in a trade business, because labour margins are fixed and volume is constrained by time on the tools.
Exclusive vs shared leads
In UK trade lead generation, an exclusive lead is a homeowner enquiry sold to one contractor only, whereas a shared lead is the same enquiry sold simultaneously to multiple businesses — typically three to six — competing for the same job. Exclusive leads carry a significantly higher unit price (commonly £45 to £120 per lead in 2026 for home improvement trades) but deliver higher conversion rates because there is no immediate price competition at first contact. Shared leads are cheaper per unit but require faster response times and tend to push conversations towards price comparison rather than value. The choice between the two models has direct implications for a trade's cost per acquired customer and average job margin.
FMB (Federation of Master Builders)
The Federation of Master Builders (FMB) is the UK's largest trade association for small and medium-sized (SME) building companies, founded in July 1941 by 15 small builders during the post-Blitz reconstruction effort. It operates as a not-for-profit membership organisation and is the largest Scheme Provider within TrustMark, the only Government-Endorsed Quality Scheme for domestic work. New members must pass an independent inspection and vetting process before joining; existing members are subject to ongoing quality monitoring. The FMB badge is a widely recognised trust signal for consumers hiring building contractors, and membership provides access to contract templates, insurance products, dispute resolution, and policy lobbying.
Google Business Profile
Google Business Profile (GBP) is a free listing tool from Google that enables trades businesses to appear in Google Search and Google Maps when local customers search for services nearby. When a homeowner types 'electrician near me' or 'emergency plumber in Leeds', verified GBP listings populate the Local Pack — the three-business map block that sits at the top of local results. Complete, optimised profiles generate approximately 81 customer actions per month (calls, website clicks, direction requests). Despite this, 26% of UK SMBs lack a GBP entirely and only 41% have fully claimed and completed their profile.
Google Local Pack
The Google Local Pack — also called the Map Pack or Local 3-Pack — is the block of three business listings displayed at the top of Google Search results for queries with local intent, accompanied by a map. For searches such as 'plumber near me' or 'emergency electrician Birmingham', the Local Pack appears before organic website results and captures the highest share of clicks: 42% of local queries result in a Map Pack click, and Local Pack listings receive 5 times higher conversion rates than organic results alone. Ranking in the top three positions is determined by three factors Google states publicly: relevance, distance, and prominence (a combination of reviews, citations, and overall online authority).
Lead aggregator
A lead aggregator is a digital platform that collects homeowner project enquiries — typically through pay-per-click advertising, SEO, or comparison sites — and sells or distributes those enquiries as actionable leads to tradespeople and contractors. In the UK home improvement sector, well-known aggregators include Checkatrade, MyBuilder, Bark.com, and Rated People. Aggregators operate on two primary revenue models: pay-per-lead, where the tradesperson pays a fee each time they receive an enquiry, and subscription, where a monthly fee grants access to a capped volume of leads in a chosen geography and trade category. Lead quality varies significantly between platforms; aggregators that verify enquiries before distribution command premium pricing.
Missed Call Rate
Missed Call Rate is the percentage of inbound telephone enquiries that a business fails to answer in real time. For UK tradespeople — who typically work alone or in small teams and are physically on-site during working hours — missed call rates of 27-47% are common. Research by Paperclip (2017, 300 UK micro-businesses) found that one in three calls from micro-businesses went unanswered; a 2025 study of 142 UK SMEs found nearly half (47%) of initial calls unanswered. Because 85% of callers who are not answered do not call back, a high missed call rate translates directly into lost revenue.
MyBuilder
MyBuilder is a UK pay-per-shortlist lead platform for domestic trades. Homeowners post jobs for free; tradespeople browse matching leads and send a free introduction message. A fee of £2–£35 (depending on job size) is charged only when the homeowner shortlists the tradesperson and contact details are exchanged. All registered tradespeople are ID-checked and skill-assessed before joining.
NAP Consistency
NAP Consistency refers to having a business's Name, Address, and Phone number recorded identically across every online citation — Google Business Profile, Apple Maps, Bing Places, Checkatrade, Yell, Facebook, and any other directory or platform where the business appears. Google uses the volume and agreement of NAP citations as a trust signal when deciding which businesses to rank in local search results and the Local Pack. Inconsistent NAP data — such as a trading name abbreviated differently on two platforms or a phone number with and without the area code — introduces conflicting signals that can suppress local rankings. Research shows that 68% of consumers stop using a local business if they find incorrect information online.
Rated People
Rated People is a UK hybrid lead platform for domestic trades that combines a monthly membership subscription with a per-lead credit system. Homeowners post jobs free of charge; up to three tradespeople can quote per job. Members pay a monthly fee (from £35 + VAT, with equivalent credit returned) and use credits to purchase the specific leads they want. Tradespeople are vetted for ID, qualifications, and insurance before activation.
TrustATrader
TrustATrader is a UK annual-subscription trade directory that vets tradespeople through qualification certificates, public liability insurance checks, and customer references before listing. The platform validates 50 per cent of positive reviews for authenticity and operates a three-strike enforcement rule. Tradespeople pay an annual fee; customer enquiries (including SMS via Textatrader) arrive as part of the membership with no additional per-lead charge.
Which? Trusted Traders
Which? Trusted Traders is a consumer-facing endorsement scheme operated by Which? — the UK's largest independent consumer organisation — that vets and publicly endorses sole traders and small businesses operating in the home improvement and maintenance sector. To earn the badge, a business must pass a multi-stage assessment conducted by Trading Standards-qualified assessors covering financial health, customer references, insurance, complaints procedures, and an on-site or video inspection. Endorsed traders are listed on the public directory at trustedtraders.which.co.uk and gain access to an independent dispute-resolution service. The scheme targets homeowners who need a trustworthy shortcut when hiring a builder, electrician, plumber, or other tradesperson.
Schema and web tech8
DefinedTerm schema
DefinedTerm and DefinedTermSet are schema.org types that allow webmasters to mark up glossaries, technical vocabularies and sets of terms with precise definitions. DefinedTerm describes an individual term with its name and identifier within a set, while DefinedTermSet groups multiple terms under a shared vocabulary. This markup signals to search engines and language models that the page is an authoritative primary source of definitions, increasing its probability of citation in AI-generated responses to definitional queries.
FAQPage schema
FAQPage schema is a schema.org structured-data type that marks up a list of questions and their answers directly in a page's HTML. Google can use this markup to display expandable question-and-answer pairs beneath a search result — a rich result that increases visual presence on the SERP without requiring users to click through for basic information. In 2026, correctly marked FAQPage content is also a strong citation signal for AI answer engines extracting passages to build generative responses.
HowTo schema
HowTo schema is a schema.org structured-data type that describes a step-by-step procedure for completing a task. It lets webmasters mark up tutorial and instructional content with semantic metadata that Google can use to display rich results showing the steps of a process directly in search — including images, estimated duration and required tools or materials. AI answer engines use HowTo markup to extract and present instructions in structured form, citing the original source.
JSON-LD
JSON-LD (JavaScript Object Notation for Linked Data) is a W3C standard serialisation format for structured data. It embeds machine-readable facts inside a webpage as a self-contained JSON script block — separate from the visible HTML — so crawlers and AI agents can extract entity information without parsing prose. Google, Bing, and the major AI assistants give JSON-LD the highest reliability rating among the three structured-data formats (JSON-LD, Microdata, RDFa). For UK trade businesses, JSON-LD is the delivery mechanism for LocalBusiness, Service, FAQPage, and Review schema types that power rich results and AI-generated answers.
LocalBusiness schema
LocalBusiness schema is a structured-data vocabulary from Schema.org that lets businesses embed machine-readable facts — name, address, telephone, opening hours, geo-coordinates, service areas, price range, and aggregate ratings — directly inside a webpage's HTML as JSON-LD. Search engines and AI assistants consume this markup to populate Knowledge Panels, Local Packs, and AI-generated answers without scraping prose. For tradesmen and home-services firms, correct LocalBusiness markup is the single highest-leverage technical action for visibility in both traditional local search and AI-powered discovery in 2026.
Organization schema
Organization schema is a schema.org structured-data type that lets a business describe its digital identity in a machine-readable form: legal name, logo, address, contact channels, social profiles and area of activity. Google uses this markup to build a knowledge panel for the company in search results and to establish the corporate entity as a reference point in generative AI systems, improving consistency of information across every digital touchpoint.
sameAs
sameAs is a Schema.org property that declares the canonical URLs of all external profiles and authority sources that refer to the same real-world entity as the current webpage. By listing a business's Google Business Profile URL, Companies House page, Wikidata entry, and verified social profiles inside a JSON-LD block, sameAs stitches together disparate web mentions into a single Knowledge Graph node. Search engines and AI systems use this entity resolution to confidently surface, cite, and recommend the business across queries — regardless of which source the user visited first.
Schema markup
Schema markup is a structured-data vocabulary maintained by schema.org that lets webmasters annotate HTML with machine-readable semantic metadata. Expressed as JSON-LD embedded in the page, it tells Google, Bing and AI answer engines exactly what a page is about, who published it and what claims it makes — without forcing any system to infer meaning from prose alone. Correct implementation unlocks rich results in search and increases the probability of citation in generative AI responses.
Regulation6
Companies House
Companies House is the executive agency of the UK Government, sponsored by the Department for Business and Trade, responsible for incorporating and dissolving limited companies and registering company information. Every limited company formed in England and Wales, Scotland, or Northern Ireland must be registered with Companies House before it can legally trade as a limited entity. Upon incorporation, a company receives a unique Company Registration Number (CRN) and a Certificate of Incorporation. Companies must file annual accounts, a Confirmation Statement (formerly the Annual Return), and notify Companies House of changes to directors, registered office, and persons with significant control (PSCs). All filed information is available to the public free of charge via the Companies House register.
Gas Safe Register
Gas Safe Register is the official gas engineering register for the United Kingdom, Isle of Man, and Guernsey, appointed by the Health and Safety Executive (HSE) under the Gas Safety (Installation and Use) Regulations 1998. It replaced CORGI as the sole approved register in April 2009. Under Regulation 3 of that legislation, no person may carry out gas fitting work unless they are a member of a class of persons approved by the HSE — in practice, this means being listed on Gas Safe Register. Every registered engineer carries a photo ID card showing their licence number, the gas appliances they are qualified to work on, and the card's expiry date. Members of the public can verify any engineer's credentials free of charge on the Gas Safe Register website or by calling 0800 408 5500.
NAPIT
NAPIT (National Association of Professional Inspectors and Testers) is one of the UK's largest Government-approved, UKAS-accredited certification bodies in the building services and fabric sector. It operates Competent Person Schemes across multiple disciplines including electrical installations, plumbing, heating, renewables, ventilation, fire safety, and building fabric, serving over 20,000 members. NAPIT is designated as a Government-Authorised Competent Person Scheme operator, enabling member businesses to self-certify notifiable building work under the Building Regulations without a separate local authority Building Notice. It is also a TrustMark Scheme Provider and an accredited certification body for the Microgeneration Certification Scheme (MCS).
NICEIC
NICEIC (National Inspection Council for Electrical Installation Contracting) is a UK electrical contracting industry certification body and a Government-Authorised Competent Person Scheme operator for Part P of the Building Regulations (England). Founded in 1956, it assesses and approves electrical contractors, enabling them to self-certify notifiable electrical installation work in dwellings without submitting a Building Notice to the local authority. Approved businesses are assessed against technical standards derived from BS 7671 (the IET Wiring Regulations). NICEIC operates two principal approval tiers — Approved Contractor and Domestic Installer — and is one of the largest electrical approval bodies in the UK, with tens of thousands of registered businesses.
TrustMark
TrustMark is the only UK Government-Endorsed Quality Scheme for work carried out in and around the home. Established in 2005, it is operated as a not-for-profit organisation under a Master Licence Agreement issued by the Department for Business and Trade. TrustMark does not certify individual tradespeople directly; instead it licences and audits over 35 Scheme Providers — industry bodies such as NICEIC, Gas Safe Register, the FMB, and MCS — who in turn vet and register their member businesses. A TrustMark Registered Business has agreed to a Code of Conduct, a Customer Charter, and complies with technical standards set by its relevant Scheme Provider. The scheme covers more than 156 service types and over 15,000 registered businesses across the UK.
UK GDPR
UK GDPR (UK General Data Protection Regulation) is the data protection law that governs how organisations in the United Kingdom collect, use, and store personal data. It came into effect on 1 January 2021 following the UK's departure from the European Union, replacing EU GDPR as the operative framework in UK law. UK GDPR operates alongside the Data Protection Act 2018, which supplements and amends it. The legislation is enforced by the Information Commissioner's Office (ICO), an independent supervisory authority. Organisations that process personal data must comply with six data protection principles — including lawfulness, purpose limitation, data minimisation, and accountability — and must identify a lawful basis for each processing activity.