The origin of the word tragedy is downright comical. It developed from Middle English tragedie, which was borrowed from Old French tragedie, which developed from the Latin word tragoedia, still with the modern definition. As many Latin words did, this came from Greek; in this case it was from tragoidia, which still meant "bad event" but could also describe the famous Greek tragedies, plays depicting bad events. When these plays were first invented, they needed a name of them, and since many of these tragedies depicted satyrs (half-goats) they called them "goat-songs", combining the words tragos ("goat") and oide ("song"). Tragos has an unknown origin, but seems to be Indo-European. and oide is a shortening of aeido, which means "sing", not too far of a stretch. This is from Proto-Hellenic aweido, from Proto-Indo-European hweyd, both of which also meant "song". But, yeah, goat songs. Very solemn.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.