Mon″arch (?), n. [F. monarque, L. monarcha, fr. Gr. �, �; μόνοσ alone + � to be first, rule, govern. See Archi-.] 1. A sole or supreme ruler; a sovereign; the highest ruler; an emperor, king, queen, prince, or chief.
He who reigns
Monarch in heaven,... upheld by old repute. Milton.
2. One superior to all others of the same kind; as, an oak is called the monarch of the forest.
3. A patron deity or presiding genius.
Come, thou, monarch of the vine,
Plumpy Bacchus. Shak.
4. (Zoöl.) A very large red and black butterfly (Danais Plexippus); — called also milkweed butterfly.