- Obs. the single or sole ruler of a state
- the hereditary (often constitutional) head of a state; king, queen, etc.
- a person or thing that surpasses others of the same kind
- a large, migratory butterfly (Danaus plexippus) native to North America, having orange, black-edged wings: the larvae feed on milkweed
Origin of monarchLate Middle English monarcha from Late Latin from Classical Greek monarch?s from monos, alone + archein, to rule: see mono- and -arch