n. (pl. -ies) 1 the cruel and arbitrary use of authority. 2 a tyrannical act; tyrannical behaviour. 3 a rule by a tyrant. b a period of this. c a State ruled by a tyrant. tyrannous adj. tyrannously adv.
[ ME f. OF tyrannie f. med.L tyrannia f. Gk turannia (as TYRANT) ]