bufflehead n.

1580s (earlier buffel, 1510s, from French), from Portuguese bufalo "water buffalo," from Medieval Latin bufalus, variant of Latin bubalus "wild ox," from Greek boubalos "buffalo," originally the name of a kind of African antelope, later used of a type of domesticated ox in southern Asia and the Mediterranean lands, a word of uncertain origin. It appears to contain bous "ox, cow" (from PIE root *gwou- "ox, bull, cow"), but this is perhaps Greek folk-etymology.

It has been wrongly applied since 1630s to the American bison. The other Germanic words (Dutch buffel, German Büffel, Danish böffel, etc.) are from French; from Medieval Latin come Russian buivolu, Polish bujwoł, Bulgarian bivol, etc. Buffalo gnat is recorded from 1822. Buffalo chip "dung of the American bison," used for fuel on the U.S. plains, is from 1840.

Old English heafod "top of the body," also "upper end of a slope," also "chief person, leader, ruler; capital city," from Proto-Germanic *haubid (source also of Old Saxon hobid, Old Norse hofuð, Old Frisian haved, Middle Dutch hovet, Dutch hoofd, Old High German houbit, German Haupt, Gothic haubiþ "head"), from PIE root *kaput- "head."

Modern spelling is early 15c., representing what was then a long vowel (as in heat) and remained after pronunciation shifted. Of rounded tops of plants from late 14c. Meaning "origin of a river" is mid-14c. Meaning "obverse of a coin" (the side with the portrait) is from 1680s; meaning "foam on a mug of beer" is first attested 1540s; meaning "toilet" is from 1748, based on location of crew toilet in the bow (or head) of a ship.

Synechdochic use for "person" (as in head count) is first attested late 13c.; of cattle, etc., in this sense from 1510s. As a height measure of persons, from c. 1300. Meaning "drug addict" (usually in a compound with the preferred drug as the first element) is from 1911.

To be over (one's) head "beyond one's comprehension" is by 1620s. To give head "perform fellatio" is from 1950s. Phrase heads will roll "people will be punished" (1930) translates Adolf Hitler. Head case "eccentric or insane person" is from 1966. Head game "mental manipulation" attested by 1972.