\label

LaTeX2e help 1.6

### 2.2.1: \label

`\label{key}`

A `\label` command appearing in ordinary text assigns to the `key` the number of the current sectional unit; one appearing inside a numbered environment assigns that number to the `key`.

A `key` can consist of any sequence of letters, digits, or punctuation characters. Upper and lowercase letters are different.

To avoid accidentally creating two labels with the same name, it is common to use labels consisting of a prefix and a suffix separated by a colon. The prefixes conventionally used are

- `cha` for chapters
- `sec` for lower-level sectioning commands
- `fig` for figures
- `tab` for tables
- `eq` for equations

Thus, a label for a figure would look like `fig:bandersnatch`.