# Glossary

Source: https://capacms.com/docs/glossary

The words Capa uses, and the older API names you will meet for the same things.

The admin and these docs say **project** and **entry**. Parts of the API, older code and some error messages say **tenant** and **instance**. They mean the same things.

| Term                       | Means                                                                                                                                                                    |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Project**                | One site's space in Capa: its models, entries, media, keys and members. The API calls it a **tenant**. See [Projects](https://capacms.com/docs/concepts/projects).                          |
| **Model**                  | A content type you define, such as Article. The API sometimes calls it a **data model**.                                                                                 |
| **Namespace**              | A model's or a field's name in the API, such as `article` or `hero_image`. Lowercase, unique within its project or model.                                                |
| **Field**                  | One value on a model: text, a number, an image, a link. See [Content model](https://capacms.com/docs/concepts/content-model).                                                               |
| **Entry**                  | One piece of content of a model. The API calls it an **instance**: the `instance:read` scope reads entries, and `instance.published` is the webhook event for a publish. |
| **Version**                | One saved state of an entry. Every save makes a new one, and one of them is live.                                                                                        |
| **Draft**                  | An entry, or a version of one, that is not live. Only draft keys can read it.                                                                                            |
| **Published**              | Live. Production keys read the published version.                                                                                                                        |
| **Published, draft ahead** | Live, with saved changes that are not live yet. The API's `status` for it is `changed`.                                                                                  |
| **Relation**               | A field that links to entries of another model, such as an article's author.                                                                                             |
| **Expand**                 | Ask for a related entry's own fields in the same read: `select=title,author(name)`.                                                                                      |
| **Select**                 | The `select` parameter: which fields a read returns.                                                                                                                     |
| **Key**                    | The credential your code reads with, sent in `x-api-key`. See [Keys](https://capacms.com/docs/concepts/keys).                                                                               |
| **Scoped key**             | A key starting `cap_live_` or `cap_test_`. It carries scopes and works on `/api/`.                                                                                       |
| **Legacy key**             | A key starting `pk_` or `sk_`, or an older key with no prefix. It works on `/v2/api`, `/v3/api` and `/api/`.                                                             |
| **Production key**         | A key that reads published entries only: `cap_live_` or `pk_`. Its reads are cached.                                                                                     |
| **Draft key**              | A key that reads drafts too: `cap_test_` or `sk_`. The API reports its environment as something other than `production`. Never cached.                                   |
| **Scope**                  | One permission on a scoped key, written `resource:action`, such as `instance:read`.                                                                                      |
| **Version (API)**          | The dated contract a read follows, such as `2026-10-01`, sent in `Capa-Version`. See [Versions](https://capacms.com/docs/concepts/versions).                                                |
| **Surrogate key**          | A tag on a cached response that names what it holds, so a publish purges exactly the responses that showed the entry. See [Caching](https://capacms.com/docs/concepts/caching).             |
| **Purge**                  | Clearing cached responses. Publishing purges what changed.                                                                                                               |
| **Workspace**              | An arrangement of the admin's sidebar: folders and shortcuts. Moving things in it never moves content.                                                                   |
| **Layout**                 | How a model's entries are arranged in the editor: cards, columns and widths.                                                                                             |
| **Owner**                  | The one person in a project who can transfer it or delete it.                                                                                                            |
| **Role**                   | What a member may do: Admin, Developer, Content or Viewer. See [Members and roles](https://capacms.com/docs/projects/members-and-roles).                                                    |
| **Legacy API**             | `/v2/api` and `/v3/api`, the read API existing sites use. It keeps working.                                                                                              |