Mm: Monad (Gr. Monas, a unit)

1. In Greek usage, originally the number one. Later, any individual or metaphysical unit.
2. Bruno named his metaphysical units monads to distinguish them from the Democritean atoms. The monads, centers of the world life, are both psychic and spatial individuals.
3. Leibniz (borrowing the term possibly from Augustine, Bruno or Protestant scholastics) identified the monads with the metaphysical individuals or souls, conceived as unextended, active, indivisible, naturally indestructible, teleological substances ideally related in a system of pre-established harmony.
4. By extension of Leibnizian usage, a soul, self, metaphysical unit, when conceived as possessing an autonomous life, and irrespective of the nature of its relations to beings beyond it.

-- W.L.