[Koshkin]

> A monad is just a monoid in the category of endofunctors

A helpful analogy can be drawn by comparing two facts: a composition of something with its inverse produces the identity (a.k.a. unity, to use the Latin root), while a composition of something (e.g. a functor) with its "adjoint" (not quite the inverse) produces something similar that is better said in Greek.

[infogulch]

And thus, another cycle is completed.