Linked from
The 13 pages that link to Monoid, each with the reason it gives.
AssociativityBroader topic: Adding an identity to an associative operation produces a monoid.
Binary operationBroader topic: A monoid adds a neutral element to an associative operation.
SemigroupBroader topic: A monoid is precisely a semigroup with a neutral element.
Associative propertyBroader topic: Adding an identity to an associative operation yields a monoid.
MagmaBroader topic: A monoid adds associativity and an identity to the magma framework.