# Category:Definitions/One

This category contains definitions related to One.

The cardinal associated with the singleton $\left\{{\varnothing}\right\}$ is called one, and is denoted $1$.

More informally, this means that one is defined as being the number of elements in a singleton set.

## Pages in category "Definitions/One"

The following 3 pages are in this category, out of 3 total.