# Labels and tags

Labels, references, and equation tags.

https://texform.dev/latex/topics/cross-refs

This topic has 6 commands from the ams, base, and textmacros packages. Commands show whether MathJax, KaTeX, and XeTeX render them. Entries are ordered by how often they appear in corpus formulas.

Packages: ams (3), base (3), textmacros (2).

| Name | Kind | Definition | Packages | MathJax | KaTeX | XeTeX | Frequency |
| --- | --- | --- | --- | --- | --- | --- | --- |
| [\\label](https://texform.dev/latex/commands/label) | command | Labels an equation or displayed math expression so it can be referenced later with commands like \ref. | base | full | none | full | 0.02% |
| [\\ref](https://texform.dev/latex/commands/ref) | command | Used for cross-references to previously labeled equations or other numbered objects in mathematical expressions. | base, textmacros | full | none | full | <0.01% |
| [\\nonumber](https://texform.dev/latex/commands/nonumber) | command | Suppresses automatic equation numbering for a particular row or display in multiline equation environments and other taggable displayed-math contexts. | base | full | full | full | <0.01% |
| [\\eqref](https://texform.dev/latex/commands/eqref) | command | Referencing a numbered equation by label, typically producing a parenthesized equation number in AMS math input. | ams, textmacros | full | none | partial | <0.01% |
| [\\notag](https://texform.dev/latex/commands/notag) | command | Used inside AMS display environments such as align or gather to suppress the equation number/tag for the current row | ams | full | full | full | <0.01% |
| [\\tag](https://texform.dev/latex/commands/tag) | command | Used to override or supply a custom equation tag/number in AMS display math, with an optional starred form for an unparenthesized tag. | ams | full | none | none | 0% |