More generally, in any group, or even any monoid, the group operation is often called ‘multiplication’ and written as juxtaposition, and then the neutral element$\mathrm{e}$ is sometimes also denoted “$1$”. As a consequence, in any ring, or more generally any rig, the two binary operations are called ‘addition’ and ‘multiplication’, and the identity for multiplication is called one.

Categorifying this idea, in any monoidal category the unit object may be called one, best denoted now by a bolder font, such as $\mathbb{1}$. This is especially true in the case of a cartesian monoidal category, that is a category with (at least finitary) products. In this case the terminal object, which serves as the identity for products, is often denoted “$1$”: