| Atom | One line of a text file, with an identity: the change that introduced it and an index. |
| Attestation | A signed statement about a bookmark move, a tag, a batch of changes, a key or a receipt. |
| Bookmark | A named pointer to a state that can move. Oxygen's branch. |
| Change | The unit of history: what was done to files and lines, and which changes it builds on. |
| ChangeHash | A change's content hash. Any edit gives a new one. Written #7469d16c. |
| ChangeId | A change's stable random ID, kept across rewrites. Written 658990aa. |
| Checkpoint | A saved materialisation of a state, so loading need not replay all history. |
| Chunk | A piece of file content, cut where the content says (FastCDC), so edits share most chunks. |
| Commute | Two changes commute when neither depends on the other: either order gives the same result. |
| Conflict | A file or tree whose live content has no single order. It is recorded, not refused. |
| Delegate | A key allowed to act for an identity within a scope: changes, seal or refs. |
| Dependency | A change another change builds on, because it touches what that one introduced. |
| Head | A change in a state that nothing else in the state depends on. |
| Identity | A public key pair (Ed25519 and ML-DSA-65) with a name and email. Its hash is its KeyId. |
| Node | A file, directory or symlink, with an ID that survives renames. |
| Operation | A recorded command and the view of every bookmark and working copy after it. |
| Resolution | A change that settles a conflict, depending on every side of it. |
| Seal | One signature over a batch of change hashes, made at push. |
| State | A set of changes closed under dependencies, named by its heads. |
| Store | Where objects and the one changing record live: a directory, memory or a bucket. |
| Strata | Oxygen's pluggable storage: a repository on storage its owner chooses. |
| Tag | A named, signed pointer to a state that never moves. |
| Trust policy | The repository's own rules for which keys may move which bookmarks. |
| Working-copy change | The change that always describes the files in your directory. |