1 a serious accident, crime, or natural catastrophe.
2 a sad event; a calamity (the team's defeat is a tragedy).
3 a a play in verse or prose dealing with tragic events and with an unhappy ending, esp. concerning the downfall of the protagonist. b tragic plays as a genre (cf. COMEDY).
Etymology: ME f. OF tragedie f. L tragoedia f. Gk tragoidia app. goat-song f. tragos goat + oide song
Useful english dictionary. 2012.