Glossary

Acronyms and key terms used across UK property data. Filter live with the search box.

Organisations & bodies

Term	Full name	Role
OPDA	Open Property Data Association	UK industry body for digital property data; publishes the PDTF schema and leads the collaborative SPDTF programme.
DPMSG	Digital Property Market Steering Group	Formed 1 Aug 2023 by HMLR. 13 founding members. Central convening body.
HBSG	Home Buying and Selling Group	Industry coordination body chaired by Kate Faulkner OBE. Custodian of BASPI. (DPMSG roadmap PDF renders as "HBSC" — same body.)
NTS	National Trading Standards	UK trading standards body.
NTSELAT	National Trading Standards Estate and Letting Agency Team	Owned (now-withdrawn) Material Information rules.
DBT	Department for Business and Trade	Hosts the Smart Data Council; sponsors Smart Data Challenge; published Smart Data Roadmap.
DSIT	Department for Science, Innovation and Technology	Owns the Smart Data scheme under DMCC Act + DVSTF.
DCMS	Department for Culture, Media and Sport	Predecessor to DSIT for the data brief.
MHCLG	Ministry of Housing, Communities and Local Government	Policy lead for housing/property.
DLUHC	Department for Levelling Up, Housing and Communities	Predecessor to current MHCLG.
HMLR	HM Land Registry	Operational lead. Formed DPMSG. Runs LLC programme.
FCA	Financial Conduct Authority	Smart Data scheme regulator (precedent: Open Banking).
ICO	Information Commissioner's Office	Data protection regulator under UK GDPR / DPA 2018.
CLC	Council for Licensed Conveyancers	Sandbox delivery partner with OPDA + Raidiam.
SRA	Solicitors Regulation Authority	DPMSG founding member.
RICS	Royal Institution of Chartered Surveyors	DPMSG founding member.
CILEX	Chartered Institute of Legal Executives	DPMSG founding member.
COPSO	Council of Property Search Organisations	DPMSG founding member.
BSA	Building Societies Association	DPMSG founding member.
TPI	The Property Institute	UK industry body for property managers. Hosts NTS guidance mirror.
Raidiam	—	Trust-framework operations firm. Sandbox partner. Built UK/Brazil Open Banking.
EDM Council	Enterprise Data Management Council	Publishes DCAM (a framework not adopted by OPDA — see ToIP page for why).

Legislation & policy

Term	Full name	Role
DMCC Act 2024	Digital Markets, Competition and Consumers Act 2024	Empowers Smart Data scheme designations.
DUAA / DUA Act	Data (Use and Access) Act 2025	Modernises UK GDPR for data sharing.
LFRA 2024	Leasehold and Freehold Reform Act 2024	Leaseholder reforms; Right to Manage etc.
LRA 2002	Land Registration Act 2002	Enabled e-conveyancing in law; basis for HMLR digital programmes.
RPF	Regulators' Pioneer Fund	UK government innovation fund. Funds the Trust Framework Sandbox.
UK GDPR	UK General Data Protection Regulation	UK-adopted GDPR; basis for ICO data sharing rules.
DPA 2018	Data Protection Act 2018	UK implementation of GDPR.
MLR 2017	Money Laundering, Terrorist Financing and Transfer of Funds Regulations 2017	Identity-verification obligations on regulated participants.

Standards & frameworks

Term	Full name	Role
PDTF schema	Property Data Trust Framework schema	The existing Digital Property Pack schema: JSON Schema, overlays, data dictionary and business glossary. The ontology extracted from these sources is separate, schema-derived evidence.
ToIP	Trust Over IP Foundation	Linux Foundation project whose four-layer governance model informs OPDA's separate governance work.
DVSTF	Digital Verification Services Trust Framework	UK government trust framework for digital verification services (the rename of the former DIATF). DSIT-owned.
IDP	Identity Provider (plural IDPs)	Entity that authenticates users and issues identity claims/credentials. In OPDA context, typically a DVSTF-certified Identity Provider.
SPDTF	Smart Property Data Trust Framework	The first property scheme draft being authored collaboratively across industry and stakeholders. The PDTF schema and its separate schema-derived ontology are evidence inputs to that work.
VC	Verifiable Credentials	W3C data model for cryptographically verifiable claims, used in existing OPDA semantic and trust-framework evidence for SPDTF review.
DID	Decentralized Identifier	W3C standard for self-sovereign identifiers. Explored in legacy supporting material on `propdata.org.uk`, but not an OPDA / MHCLG / DPMSG-ratified approach — still to be tested and certified against the emerging Smart Data Guidebook and DSIT Digital Verification Services.
VCDM	Verifiable Credentials Data Model	W3C VC spec, versions 1.1 and 2.0 archived locally.
DIDComm	DID Communication	Secure-messaging protocol used between DID-identified parties. Like DID, an exploratory approach inherited from `propdata.org.uk` — not yet OPDA/MHCLG/DPMSG-ratified.
OIDC	OpenID Connect	Identity layer over OAuth 2.0. Used in separate PDTF-schema-era authentication material.
FAPI	Financial-grade API	OpenID Foundation profile of OAuth 2.0 used by Open Banking and adopted as a baseline for high-assurance API authorisation.
DCAM	Data Management Capability Assessment Model	EDM Council framework. Not the framework OPDA has chosen (ToIP is).
DAMA-DMBOK	Data Management Body of Knowledge	Broader data management reference. Component-level usable.
IDS-RAM	International Data Spaces Reference Architecture Model	EU-led reference architecture for sovereign data sharing across federated data spaces.
FAIR	Findable, Accessible, Interoperable, Reusable	Data sharing principles.
SKOS	Simple Knowledge Organization System	W3C standard for taxonomies / controlled vocabularies.
OWL	Web Ontology Language	W3C standard for ontologies.
SHACL	Shapes Constraint Language	W3C standard for validating RDF graphs.
DCAT	Data Catalog Vocabulary	W3C vocabulary for describing datasets.
RDF	Resource Description Framework	W3C foundational data model for the semantic web.
JSON-LD	JSON for Linked Data	RDF serialisation in JSON. Used in the separate ontology work that projects PDTF schema concepts into RDF.

UK property forms & data sets

Term	Full name	Role
BASPI	Buyer and Seller Property Information	HBSG's industry data set, v4 / v5. Implemented as `baspi.json`, `baspi5.json`.
TA6	Law Society Property Information Form (6th ed, 2025)	Implemented as `ta6.json`.
TA7	Law Society Leasehold Information Form (5th ed, 2025)	Implemented as `ta7.json`.
TA10	Law Society Fittings and Contents Form	Implemented as `ta10.json`.
CON29R	CON29 Residential search	Standard local authority residential search. `con29R.json`.
CON29DW	CON29 Drainage and Water	`con29DW.json`.
LPE1	Leasehold Property Enquiry	Standard leaseholder enquiry pack. `lpe1.json`.
OC1	Office Copy entries (HMLR Title)	HMLR-supplied title register copy. `oc1.json`.
LLC1	Local Land Charges search	HMLR-provided LLC register search. `llc1.json`.
PIQ	Property Information Questionnaire	Standard PIQ. `piq.json`.
RDS	Residential Data Schema	UK property data schema. `rds.json`.
FME1	Form for Mortgage Enquiries	`fme1.json`.
UPRN	Unique Property Reference Number	Persistent identifier for UK property addresses.

Programmes & initiatives

Term	Full name	Role
Sandbox	Smart Property Data Trust Framework Sandbox	CLC + OPDA + Raidiam, RPF-funded, DPMSG-governed. Live.
SDC	Smart Data Challenge	DBT-sponsored. Moverly+OPDA prototype won an SDCP Innovators prize.
SDCP	Smart Data Challenge Prize	The award stream within SDC.
LLC Programme	Local Land Charges Programme	HMLR-led migration of council LLC registers to a national digital service.
Open Banking	—	UK precedent for sector-specific trust framework + standards body separation.

Ontology modelling

These short explanations support the shared-meaning learning journey. The linked chapters show how the distinctions work in practice; the local ontology decision records define the required method.

Term	Meaning in this modelling work
Ontology	An explicit account of the things we describe, the relationships between them and the distinctions we agree to preserve. It is more than a list of words. Why shared meaning matters.
Resource	Something we identify and say things about: for example, a dwelling, a person, an inspection or a particular report version. It need not be a physical object. Things and identities.
Relationship	A named connection with a specific meaning, such as a report describing an inspection. “Related to” alone does not say enough. Classes and relationships.
Kind	What sort of thing something is, distinguished here from a role it can play or a phase it can pass through. The technical chapter explains when that distinction warrants a class relationship. Roles and phases.
Role	A capacity held in a relationship or situation, such as being a seller in a particular sale. A person can stop playing that role without becoming a different person; it does not by itself grant access to information. Roles and phases.
Phase	A condition through which the same thing can pass. Its identity is retained when the condition changes. A workflow label is not automatically an ontological phase. Roles and phases.
Claim	An assertion to examine, including what it concerns, who made it and when it applies. Recording a claim does not establish its truth. Evidence and time.
Evidence	Material or an observation that helps someone assess a claim or modelling proposal. Evidence may support, qualify or challenge an interpretation; it is not automatic approval. Bring useful evidence.
Semantic home	The documented context responsible for a meaning. It is not necessarily the team, system or screen where the term appears. Contexts and connections.
Bounded context	An explicit boundary within which meanings and their ownership are maintained consistently. OPDA's contexts are already documented: participation refines meaning within them rather than discovering a new context map. Contexts and connections.
Mapping	An explicit, scoped account of how meanings correspond across contexts or vocabularies. Similar labels are not enough to establish equivalence; a mapping can be rejected or later revised. Qualified term mappings.

OPDA programme concepts

Term	Definition
Trust Framework	Agreements + rules + technical standards by which organisations exchange verified data.
Verified Claim	A data assertion with attached provenance — who said it, when, with what evidence.
Overlay	An optional extension to the base PDTF transaction schema (e.g. `baspi5.json`).
Property Pack	The bundle of standardised property data that accompanies a transaction. HBSG initiative.
Accreditation	OPDA's separate scheme for assessing participating organisations; it is not part of the PDTF schema.
Trust Registry	Authoritative list of who is authorised to do what within a trust framework.

Original sources for the glossary entries: OPDA website, gov.uk announcements, DPMSG founding statement, propdata.org.uk About page, W3C and Trust Over IP Foundation specs — all archived in source/. Note: propdata.org.uk is a legacy developer site carrying OPDA copyright but not authored or approved by OPDA (OPDA has no editing access); the technical approaches it presents — notably DIDs — are exploratory, not OPDA/MHCLG/DPMSG-ratified.