Glossary

Home Assistant has its own words, and some of them go by another name in the code than in the UI. Here, every term has one meaning, and one page that says how it goes by everywhere: in the code, in the UI, and what it used to be called.

Use these terms the way they are defined here, in code, UI text, and documentation. In the docs on this site, terms link to their definition by themselves, the first time a page uses them: point at a word with a dotted line to see what it means.

Missing a term, or found one that could be clearer? Every term is a page in src/content/docs/glossary/: edit it, or add a new one.

A

Actionformerly service, service call: Something Home Assistant can do, like turning on a light or sending a notification. Automations, scripts, and dashboards perform actions.
Appformerly add-on, addon: Extra software that runs next to Home Assistant on Home Assistant OS, like an MQTT broker or a file editor.
Architecture decision: A decision about how Home Assistant is built, discussed and recorded in the home-assistant/architecture repository.
Area: A room or space in the home, like the kitchen, that devices and entities belong to.
Assist: Home Assistant's voice assistant. It turns what you say or type into actions.
Assist pipeline: The steps a voice command goes through: wake word, speech-to-text, the conversation agent, and text-to-speech.
Assist satellite: A device that listens for voice commands and sends them to Home Assistant, like Home Assistant Voice Preview Edition.
Attribute: Extra information that comes with a state, like the brightness of a light or the list of effects it supports.
Automation: A rule that performs actions when a trigger happens and its conditions are met, like turning on the lights at sunset when someone is home.

B

Backward-incompatible changeformerly breaking change: A change that requires users or developers to change something on their side, like their configuration or their custom integration.
Badge: A small pill at the top of a view, that shows a state at a glance, like the temperature outside.
Bashio: A library of Bash functions for apps, with helpers for reading the app's options, logging, and talking to the Supervisor API.
Beta: A test version of the next release, published a week before it, so people can find problems before everyone updates.
Blueprint: An automation, script, or template entity with blanks to fill in, so others can reuse it, like a motion light that only needs the motion sensor and the lamp.
Branch: A separate line of changes in a repository, so you can work on something without touching the main version.
Buildroot: The tool Home Assistant OS is built with. It builds a complete, small Linux system from source, instead of starting from a distribution like Ubuntu.

C

Card: A block on a dashboard that shows or controls something, like an entity, a graph, or a weather forecast.
Card feature: An extra control at the bottom of a card, like a brightness slider or buttons for a vacuum.
CI: Continuous integration: the automated checks, like tests, linters, and type checks, that run on every pull request.
CLA: The Contributor License Agreement: your confirmation that you have the right to share your contribution under the license of the project. You sign it once.
Commit: One saved change to one or more files in a repository, with a message that says what changed.
Companion app: The Home Assistant app for Android, iOS, and macOS. It shows the frontend, and adds sensors, notifications, and widgets from the device.
Condition: A check an automation or script does before it continues, like whether someone is home.
Config entry: One set-up instance of an integration, like one Hue bridge, with the configuration Home Assistant stores for it.
Config flow: The steps in the UI that set up an integration and create a config entry.
Config subentry: A part of a config entry that the user adds and manages on its own, like one AI agent of an integration that connects to an AI service.
Conversation agent: What understands a command and answers it: the built-in agent of Home Assistant, or one from an integration, like an AI service.
Coordinator: A helper that fetches data for many entities at once, on a schedule, so a device or API is asked once instead of once per entity.
Custom card: A card that is not part of the frontend, loaded by the user from a JavaScript file.
Custom integration: An integration that is not part of Home Assistant Core, installed by the user in the `custom_components` folder.

D

Dashboardformerly Lovelace, Lovelace UI: A page of cards that shows and controls the home. Users can have as many dashboards as they like.
Deploy Preview: A temporary copy of a website with the changes of a pull request, built by Netlify, to check them before they are merged.
Deprecation: Announcing that something will be removed in a later release, while it keeps working until then, so people can move on.
Design token: A named value of the design, like a color, a spacing, or a radius, used instead of a hard-coded value.
Dev branch: The branch where development happens in many Home Assistant repositories, like Home Assistant Core and the frontend. Pull requests go there.
Device: A physical device, or a service, that one or more entities belong to, like a thermostat with a temperature sensor and a humidity sensor.
Device class: What an entity measures or is, like `temperature` or `door`. It sets the icon, the units, and how the frontend shows the entity.
Diagnostics: A download with the data and state of a config entry or device, that users attach to an issue to help debug it.
Discovery: Finding devices and services, like on the network or over Bluetooth, so Home Assistant can offer to set them up.
Domain: The short, unique identifier of an integration, like `hue` or `light`. It is also the first part of every entity ID.

E

Entity: One thing Home Assistant can show, measure, or control, like a light, a temperature sensor, or a switch. Every entity has a state.
Entity category: Marks an entity as configuration or diagnostic, so it does not show up next to the main controls of a device.
Entity description: A dataclass with the fixed properties of an entity, like its key, translation key, and device class, so many similar entities can share one class.
Entity ID: The ID of an entity: its domain and an object ID, like `light.kitchen`.
Epic: A larger body of work in the home-assistant/epics repository, made up of tasks that can span several repositories.
Event: A message on the event bus that something happened, like a state change or a button press. Any code can listen to events.
Event loop: The asyncio loop that runs Home Assistant Core. Code that blocks it, like waiting on the network without `await`, stops everything else.

F

Feature request: An idea for something new in Home Assistant, shared in the feature request discussions on GitHub, where others can comment and vote.
Floor: A level of the home, like the ground floor, that holds areas.
Fork: Your own copy of a repository, on your GitHub account, where you make changes before you propose them.
Frontend: The web interface of Home Assistant, built with Lit and TypeScript, in the home-assistant/frontend repository.

H

HACS: The Home Assistant Community Store: the custom integration that installed community-made integrations, cards, and themes, until the Marketplace replaced it in 2026.11. Its catalog and tools live on.
The hass object: The `HomeAssistant` instance that integrations get, with access to the state machine, the event bus, actions, and the configuration.
Hassfest: The tool in Home Assistant Core that validates the files of every integration, like its manifest and translations, and generates files from them.
Helper: An entity that users create in the UI to hold a value or combine others, like a toggle, a number, a timer, or a group.
Home Assistant Core: The Python application at the heart of Home Assistant, with all its integrations, in the home-assistant/core repository.
Home Assistant Labs: Where users can turn on preview features: new features that work, but whose design can still change based on feedback.
Home Assistant Linkformerly Home Assistant Cloud: The optional subscription service from Nabu Casa for remote access, Amazon Alexa and Google Assistant, online speech processing, and online backups.
Home Assistant OS: The operating system made to run Home Assistant, with the Supervisor, apps, and backups. The recommended way to install Home Assistant.

I

Ingress: A way for an app to show its web interface inside Home Assistant, behind the Home Assistant login, without opening a port.
Installation type: How Home Assistant is installed: Home Assistant OS, or Home Assistant Container. They differ in what is managed for you.
Integrationformerly component: A package of code that connects Home Assistant to a device, service, or protocol, or adds a feature like automations.
Integration ownerformerly code owner: A person or team responsible for an integration, listed in its manifest, who gets notified about its issues and asked to review its pull requests.
Integration quality scale: Tiers that integrations earn by following rules for code quality and user experience: Bronze, Silver, Gold, and Platinum.
Intent: What a voice command means, like turning on the lights in an area, with the details needed to do it.
IoT class: How an integration gets its data: locally or from the cloud, and by polling or push. Set in the manifest.
Issue: A report on GitHub about a problem in a repository, like a bug, that people can discuss and track.

L

Label: A tag users put on entities, devices, areas, automations, and more, to group them their own way, like everything that uses a lot of energy.
Language leader: A native speaker who looks after one language in the intents repository, and reviews every change to it.
Lokalise: The platform where the community translates Home Assistant: the frontend, the integrations, and the companion apps.
Long-term statistics: Hourly summaries of sensor values, like the mean, minimum, and maximum, or a running total, that the recorder keeps for good, for graphs over long periods and the energy dashboard.

M

Maintainer: A contributor who can approve and merge pull requests in a repository.
Manifest: The `manifest.json` file of an integration: its domain, name, integration owners, requirements, and how it can be discovered.
Markdown: A plain text format for writing, where symbols like # and * mark headings, lists, and emphasis. The documentation is written in it.
Marketplace: The place in Home Assistant where users find and install community-made custom integrations, dashboard cards, themes, and template macros. Built in starting with 2026.11.
Merge: Taking the changes of a pull request into the repository it was proposed to. Merged means your change is in.
Moderator: A member of the community who keeps a community space, like the forum or the Discord server, friendly and safe, by applying the code of conduct.
More-info dialog: The dialog that opens when you select an entity, with its controls, its history, and its settings.
My link: A link to my.home-assistant.io that opens a page in the reader's own Home Assistant, like their integrations, or a new automation.

N

Nabu Casa: A commercial partner of the Open Home Foundation, and the official provider of Home Assistant products and services, like Home Assistant Link.

O

Open Home Foundation: The non-profit organization that owns Home Assistant and many related projects, and stands for privacy, choice, and sustainability in the smart home.
Opportunity: An issue in the roadmap repository that describes a problem worth solving, why it matters, and the solution foreseen for it.
Options flow: The steps in the UI that change the options of an existing config entry, like how often it polls.

P

Panel: A page of its own in Home Assistant, usually in the sidebar, like a dashboard, the map, or the settings.
Patch release: A smaller release with fixes, that comes out between the monthly releases, like 2026.10.1.
Person: Someone in the household, with the device trackers that tell where they are, and optionally a user account to log in with.
Platform: How an integration provides one type of entity, like the `light` platform of the Hue integration. Also used for integration platforms, files that plug into another integration.
Polling: Asking a device or service for new data on an interval. The opposite is push, where the device sends updates when something changes.
Pull request: A request on GitHub to merge a change into a repository, where it is reviewed before it goes in.

R

RAUC: The update system of Home Assistant OS. It installs a new version of the whole system next to the running one, so a device can go back when an update does not work.
Reauthentication: A flow that asks the user for new credentials when a config entry can no longer log in, without setting it up again.
Reconfigure flow: A flow that changes the settings of a config entry, like its host, without removing and adding it again.
Recorder: The integration that stores the history of states and events in a database.
Registry: Where Home Assistant keeps what it knows about entities, devices, areas, floors, and labels, and what users changed about them.
Release: A new version of Home Assistant. One comes out on the first Wednesday of every month, with patch releases in between.
Release notes: The blog post on home-assistant.io that tells what is new in a release, what changed, and what users need to do about it.
Repair: A problem Home Assistant shows users under Repairs, with what to do about it, like configuration that will stop working.
Repository: A project on GitHub: its files, and the full history of every change to them.
Requirement: A Python package from PyPI that an integration needs, listed with a pinned version in its manifest.
Resolution center: The part of the Supervisor that finds problems with the system, like low disk space, and suggests fixes for them.
Review: Reading and testing a pull request before it is merged, by maintainers, integration owners, or anyone else who wants to help.
Roadmap: The problems the Open Home Foundation wants to solve next in Home Assistant and its other projects, tracked as opportunities in the OpenHomeFoundation/roadmap repository.

S

S6 overlay: The init system in the Home Assistant base images. It starts, watches, and stops the programs of an app inside its container.
Scene: A saved set of states for entities, like dimmed lights and closed blinds for watching a movie, that can be activated in one go.
Script: A named sequence of actions that can run from an automation, a dashboard, or by voice.
Selector: Describes what kind of value a field takes, like an entity, a number, or a time, so the UI shows the right control for it.
State: The current value of an entity, like `on`, `21.5`, or `playing`, together with its attributes.
State class: How the value of a sensor behaves, like `measurement` or `total_increasing`, so Home Assistant can keep long-term statistics for it.
State machine: The part of Home Assistant Core that holds the current state of every entity.
Strategy: Code that builds a dashboard or a view from the home itself, its areas, devices, and entities, instead of a fixed configuration.
Supervisor: The part of Home Assistant OS that runs Home Assistant Core and apps, each in its own container, and handles their updates and backups.
Supervisor API: The REST API of the Supervisor, that Home Assistant Core, the command line, and apps use to manage the system, apps, backups, and updates.
Supervisor plugin: A container the Supervisor runs for the system itself, like DNS or audio, that Home Assistant Core and apps share.
Supported features: A number an entity sets to say which features of its type it supports, like a cover that can be set to a position.

T

Target: What an action works on: entities, devices, areas, floors, or labels.
Template: A snippet of Jinja2 that computes a value from states, like the average temperature of a few sensors.
Theme: A set of CSS variables that changes the colors, and some sizes, of the frontend.
Translation key: The key that points to a text in an integration's `strings.json`, so the text can be translated. Integrations use keys, not English text in the code.
Trigger: What starts an automation, like a state change, a time, or an event.

U

Unavailable: A special state for an entity that Home Assistant can't reach right now. Its counterpart, unknown, means it can be reached but has no value yet.
Unique ID: An ID that an integration gives an entity or config entry, which never changes, so Home Assistant recognizes it after a restart.

V

View: One page of a dashboard. Its type, like sections, masonry, or panel, decides how its cards are laid out.

W

Wake word: The word or phrase that makes a voice assistant start listening, like "Okay Nabu".
WebSocket API: The API of Home Assistant Core that the frontend and the companion apps use, over one open connection, to read states, perform actions, and get updates as they happen.
Works with Home Assistant: A program of the Open Home Foundation that certifies devices that work well and locally with Home Assistant, from makers that commit to supporting them.

Y

YAML: A text format for configuration and data, with indentation for structure. Home Assistant uses it for its configuration files, and much more.

Z

Zone: A place on the map, like home, work, or school, that people can be in.