Some of these definitions will come from published guidance such as the National Planning Policy Framework (NPPF) but others will be those I’ve spotted over the years in things like Case Law or Appeal Decisions.  I think they are all useful in their own way.  By the way, its a live list so I add things as I come across them, sorry its not necessarily in alphabetical order (maybe a job for a wet Sunday afternoon …)

• Affordable Housing: This refers to housing that is available for sale or rent to individuals whose needs are not adequately met by the market. This includes options for subsidised homeownership and housing for essential local workers.
• Air Quality Management Areas: These are areas that have been designated because they exceed or are at risk of exceeding air quality standards.
• Brownfield Land: Also known as previously developed land, this is land that has been previously used for industrial or commercial purposes. It may be contaminated.
• Community Infrastructure Levy: While not defined in the provided glossary, the document “Planning practice guidance – GOV.UK” lists ‘Community Infrastructure Levy’ as a category of planning practice guidance.
• Conservation Area: An area designated for its special architectural or historic interest, the character or appearance of which it is desirable to preserve or enhance.
• Design Code: This is a set of specific, detailed, and illustrated requirements for the physical development of a site or area. It builds upon a design vision, such as a masterplan.
• Design Guide: A document, often produced by a local authority, that provides guidance on how development can be carried out in accordance with good design practice.
• Designated Heritage Asset: This includes World Heritage Sites, Scheduled Monuments, Listed Buildings, Protected Wreck Sites, Registered Parks and Gardens, Registered Battlefields, and Conservation Areas. These are designated under relevant legislation.
• Designated Rural Areas: These areas include National Parks, National Landscapes, and areas designated as ‘rural’ under Section 157 of the Housing Act 1985.
• Developable: For sites to be considered developable, they should be in a suitable location for housing development, with a reasonable prospect that they will be available and viably developed at the point envisaged.
• Development Plan: This is defined in Section 38 of the Planning and Compulsory Purchase Act 2004 and includes adopted local plans, neighbourhood plans that have been made, published spatial development strategies, and any regional strategy policies that remain in force.
• Early Years: The provision of childcare (including education) for a young child, meaning a child from birth to the September after the child turns 5.
• Edge of Centre: For retail, this is a location well connected to and within 300 meters of the primary shopping area. For other main town centre uses, it is within 300 meters of a town centre boundary. For office development, it includes locations outside the town centre but within 500 meters of a public transport interchange.
• Environmental Impact Assessment: This is a procedure followed for certain projects to ensure decisions are made with full knowledge of likely significant environmental effects.
• Essential Local Workers: Public sector employees who provide frontline services in areas such as health, education, community safety, and social care. Examples include NHS staff, teachers, police, firefighters, military personnel, social care, and childcare workers.
• General Aviation Airfields: These are licensed or unlicensed aerodromes with hard or grass runways, often with extensive areas of open land related to aviation activity.
• Geodiversity: The range of rocks, minerals, fossils, soils, and landforms.
• Green Infrastructure: This refers to a network of multi-functional green and blue spaces and other natural features, both urban and rural. It delivers a wide range of environmental, economic, health, and wellbeing benefits.
• Grey Belt: Land in the Green Belt comprising previously developed land and/or any other land that does not strongly contribute to Green Belt purposes. It excludes land where policies relating to areas or assets would provide a strong reason for refusing or restricting development.
• Gypsies and Travellers: Persons of nomadic habit of life whatever their race or origin. This includes those who have ceased to travel temporarily or permanently due to educational, health needs, or old age, and all other persons with a cultural tradition of nomadism or living in a caravan, but excluding members of an organised group of travelling showpeople or circus people travelling together as such.
• Highway: A public right of way such as a public road, public footpath, and bridleway, also including unadopted streets or private ways.
• Local Green Space: Green areas of particular importance to local communities, designated through local and neighbourhood plans.
• Local Planning Authority: The public authority responsible for carrying out specific planning functions in a particular area.
• Local Plan: A plan for the future development of a local area, drawn up by the local planning authority in consultation with the community. It can consist of either strategic or non-strategic policies, or a combination of the two.
• Neighbourhood Development Order: An order made by a local planning authority through which parish councils and neighbourhood forums can grant planning permission for a specific development proposal or classes of development.
• Neighbourhood Plan: A plan prepared by a parish council or neighbourhood forum for a designated neighbourhood area.
• People with Disabilities: Individuals with a physical or mental impairment that has a substantial and long-term adverse effect on their ability to carry out normal day-to-day activities.
• Permission in Principle: A form of planning consent establishing that a site is suitable for a specified amount of housing-led development in principle. A grant of technical details consent is required before development can proceed.
• Pitch: A pitch on a “gypsy and traveller” site.
• Plan-making authorities: Those authorities responsible for producing strategic policies. This includes local planning authorities, and elected Mayors or combined authorities, where this power has been conferred.
• Planning Condition: A condition imposed on a grant of planning permission or included in a Local Development Order or Neighbourhood Development Order.
• Planning Obligation: A legal agreement under Section 106 of the Town and Country Planning Act 1990 to mitigate the impacts of a development proposal.
• Plot: A pitch on a “travelling showpeople” site (often called a “yard”).
• Playing Field: The whole of a site which encompasses at least one playing pitch as defined in the Town and Country Planning (Development Management Procedure) (England) Order 2015.
• Primary Shopping Area: A defined area where retail development is concentrated.
• Priority Habitats and Species: Species and Habitats of Principal Importance included in the England Biodiversity List published by the Secretary of State under Section 41 of the Natural Environment and Rural Communities Act 2006.
• Ramsar Sites: Wetlands of international importance, designated under the 1971 Ramsar Convention.
• Reasonable Future Scenarios: A range of realistic transport scenarios tested in agreement with the local planning authority and other stakeholders to assess potential highways impacts.
• Safeguarded Land: Areas between the urban area and the Green Belt, identified to meet longer-term development needs beyond the plan period.
• Site of Special Scientific Interest: Sites designated by Natural England under the Wildlife and Countryside Act 1981.
• Spatial Development Strategy: A plan containing strategic policies prepared by a Mayor or a combined authority. It includes the London Plan and plans prepared by combined authorities that have been given equivalent plan-making functions.
• Stepping Stones: Pockets of habitat that facilitate the movement of species across otherwise inhospitable landscapes.
• Strategic Environmental Assessment: A procedure requiring the formal environmental assessment of certain plans and programmes likely to have significant environmental effects.
• Strategic Policies: Policies and site allocations addressing strategic priorities in line with Section 19 (1B-E) of the Planning and Compulsory Purchase Act 2004.
• Supplementary Planning Documents: Documents that add further detail to the policies in the development plan. They provide guidance for development on specific sites or particular issues, such as design.
• Terrace house: A dwellinghouse situated in a row of 3 or more dwellinghouses used or designed for use as single dwellings.
• Transport Assessment: A comprehensive and systematic process that considers and sets out transport issues relating to a proposed development. It identifies measures to support alternatives to the car and promote accessibility and safety.
• Transport Statement: A simplified version of a transport assessment used where the transport issues arising from development proposals are limited.
• Travel Plan: A long-term management strategy for an organisation or site detailing how agreed sustainable transport objectives are to be delivered. It is monitored and regularly reviewed.
• Travelling Showpeople: Members of a group organised to hold fairs, circuses, or shows. This includes those who have ceased to travel temporarily or permanently due to localised trading patterns, educational or health needs, or old age, but excludes Gypsies and Travellers.
• Vision-Led Approach: An approach to transport planning based on setting outcomes for a development based on achieving well-designed, sustainable and popular places, and providing the transport solutions to deliver those outcomes as opposed to predicting future demand to provide capacity.
• Wildlife Corridor: Areas of habitat connecting wildlife populations.
• Custom Build: Custom build involves commissioning or building a new home on a multi-plot site through various housing delivery models, facilitated or supported by a landowner, developer, contractor, or enabler. Custom builders commit to delivering their new home as part of a pre-defined process when they agree to purchase a serviced plot of land, including taking the responsibility to construct their home themselves. This commitment typically requires them to act within defined parameters designed to manage house design and size as well as the timescale for construction.
• Serviced Plot Model: In this model, the occupier can purchase a serviced plot with planning permission to construct a new home designed within a set of pre-agreed parameters, often facilitated by a Design Code, which manages the permissible house design, tenure, size, and specification on each plot. Serviced plots can be sold with the foundations already constructed (‘Golden Brick’), enabling the seller to recover VAT charged on earlier stages of the site development.
• Customisable Homes: This model offers purchasers the opportunity to customise a pre-designed new home. Customisable home sales often include the sale of a serviced plot with a separate but related design and build contract for constructing a new home to a customised design, either to completion or an agreed stage, enabling purchasers to self-finish their homes or move into a fully completed home. Design choices are managed via a menu of choices, with enough flexibility to enable the occupier to customise their home.
• Local Authority: In England, local authorities have specific obligations concerning self-build and custom housebuilding.
  • They must keep a register of people and groups seeking to acquire land to build a home in the authority’s area and consider this register when carrying out their functions, as per the Self-build and Custom Housebuilding Act 2015.
  • The Housing and Planning Act 2016 requires local authorities in England to grant sufficient ‘development permissions’ to meet the demand for custom and self-build housing in their area, as established by their register, on a rolling basis.
  • Local authorities must give suitable development permission to enough suitable serviced plots of land to meet the demand for self-build and custom housebuilding in their area. There is no duty on a relevant authority to permission land which specifically meets the requirements expressed by those on the register.
• NaCSBA (National Custom & Self Build Association): NaCSBA’s mission is to make custom and self-build a mainstream choice for those seeking a home. NaCSBA commissioned a report to track custom and self-build. In November 2017, NaCSBA found that there were 33,000 people signed up to Right To Build registers.
• Right to Build: The Right to Build is a term referring to legislation supporting the growth of custom and self-build homes in England.
  • The Right to Build legislation sets out the framework and what it can deliver for those wanting to build or design their own home in England. The government aimed to double the number of self-build and custom build homes by 2020.
  • The Right to Build went live on April 31, 2016, with the Housing & Planning Act. Local authorities in England are required to host a Right To Build Register to evidence the number of people who want to build or create their own home.
  • The registers are paired with a duty for the council to supply sufficient serviced plots for the people on their registers. Councils have three years to permission these plots from the registration date, with each three-year cycle starting from October 31.
  • You can sign up to your local council’s register here, as well as other areas where you may consider living.
• Right to Build Task Force: Established by NaCSBA in 2017, the Task Force supports the delivery of the Right to Build by providing technical expertise and advice. It works with local authorities and the private sector, offering online resources and commissioned bespoke professional support. Expertise includes compliance with Right to Build legislation, strategic planning, policy and guidance, demand, and advice on delivery, including affordable housing.
• Self-Build: Self-build involves the occupier of a new home taking responsibility for the design, construction, and funding of the home on a single building plot. The individual bears the financial costs of securing the plot and procuring the construction, including infrastructure and servicing requirements. Self-builders control their development timeline and are not bound by requirements to satisfy a developer, contractor, landowner, or enabler, except for statutory requirements from a mortgage lender, insurer, or local planning authority.
• Self-build and Custom Housebuilding Act 2015: This act provides a legal definition of self-build and custom housebuilding, not distinguishing between the two. It defines them as instances where individuals, associations of individuals, or those working with them build or complete houses to be occupied as homes by those individuals.
• Serviced Plot of Land: A serviced plot has access to a public highway and connections for electricity, water, and wastewater, or can be provided with these within the duration of a development permission. Access to a public highway can include sections of private or unadopted road, and connections mean the services are provided to the plot boundary for connection during construction, or adequate alternative arrangements are possible