# A category with a single object is a monoid¶

Any category with a single object is a monoid. The object in a monoidal category can have any number of morphisms greater than 1 - the requirement for an identity morphism isn't relaxed.

## References¶

## Backlinks¶

- Monoid
- A set-theory monoid and a category-theory monoid are the same thing
- The set theory definition and the category theory definition of monoids are different views over the same concept. Category theory defines a monoid as any category with a single object. Set theory defines a monoid as a set with an associative binary operation and a unit element.