Definition of monads:
(n) :
One thing, one being, one item.
(n) :
A group of entities or items treated as one entity.
(n) :
(philosophy) An ultimate atom, or simple, unextended point; something ultimate and indivisible.
(n) :
(functional programming) A data type which represents a specific form of computation, along with the operations "return" and "bind".
(n) :
(category theory) A monoid object in the category of endofunctors of a fixed category.
(n) :
(biology, dated) A single-celled organism. (See Monas.)