Monad
WordNet
noun
(1) (biology) a single-celled microorganism (especially a flagellate protozoan)
(2) A singular metaphysical entity from which material properties are said to derive
(3) (chemistry) an atom having a valence of one
WiktionaryText
Noun
- An ultimate atom, or simple, unextended point; something ultimate and indivisible.
- A monoid in the category of endofunctors.