Mōn'ad, n.

(Synop., § 130), n. [Fr. & It. monade, Sp. monada, Lat. monas, monadis, Gr. μονάς, μονάδος, unity, unit, from μονάς, solitary, alone, from μόνος, alone.]

1. An ultimate atom, or simple, unextended point; something ultimate and indivisible.
2. (Philos. of Leibnitz.) The elementary and indestructible units which were conceived as endowed with the power of giving and receiving with respect to others, and thus determining all physical and spiritual phenomena.
3. (Zoöl.) One of the simplest kind of minute animalcules. Dana.