Commit Hash
In plain terms
A unique identifier for a specific commit.
Going deeper
A commit hash is a SHA fingerprint uniquely identifying a commit and its exact content and history. It's the commit's permanent address.
Under the hood
Computed from content and parents, so it's tamper-evident; short prefixes usually suffice to reference.
Examples
git log SHAs, referencing commits, a1b2c3d, checkout by hash.
Think of it like...
Like a unique fingerprint stamped on every saved version.