Alexander the Great's favorite horse, from Greek Boukephalos, literally "Ox-head," from bous "ox" (from PIE root *gwou- "ox, bull, cow") + kephalē "head" (see cephalo-).

Men called [him] Bucephalus ... of the marke or brand of a buls head, which was imprinted vpon his shoulder. [Pliny, I.220, tr. Holland, 1601]

"against, over against, opposite, on the opposite side; on the contrary, contrariwise," mid-14c., from Latin contra (prep. and adv.) "against," originally "in comparison with," ablative singular feminine of *com-teros, from Old Latin com "with, together" (see com-) + -tr, zero-degree form of the comparative suffix -ter-.

any tree of the genus Citrus, or its fruit, 1825, from the Modern Latin genus name, from Latin citrus "citron tree," the name of an African tree with aromatic wood and lemon-like fruit, the first citrus fruit to become available in the West. The name, like the tree, is probably of Asiatic origin [OED] or from a lost non-IE Mediterranean language [de Vaan]. But Klein and others trace it to Greek kedros "cedar," perhaps via Etruscan (a suggested by the change of -dr- to -tr-).

by 1987, abbreviation for neo-conservative in the U.S. political sense.

Neoconservatism is the first variant of American conservatism in the past century that is in the 'American grain.' It is hopeful, not lugubrious; forward-looking, not nostalgic; and its general tone is cheerful, not grim or dyspeptic. Its 20th-century heroes tend to be TR, FDR, and Ronald Reagan. Such Republican and conservative worthies as Calvin Coolidge, Herbert Hoover, Dwight Eisenhower, and Barry Goldwater are politely overlooked. [Irving Kristol, "The Neoconservative Persuasion," in The Weekly Standard, Aug. 25, 2003]