butter: [OE] The ultimate source of butter is Greek boútūron. This is usually said to be a compound noun, formed from boús ‘cow’ and tūros ‘cheese’, but not all etymologists accept the admittedly attractive hypothesis that butter was once ‘cow-cheese’, preferring to see the Greek word as a foreign borrowing. In Latin it became būtyrum (from which came French beurre), which was borrowed into the West Germanic languages, producing English and German butter and Dutch boter. => cow
butter (n.)
Old English butere "butter," general West Germanic (compare Old Frisian, Old High German butera, German Butter, Dutch boter), an early loan-word from Latin butyrum "butter" (source of Italian burro, Old French burre, French beurre), from Greek boutyron, perhaps literally "cow-cheese," from bous "ox, cow" (see cow (n.)) + tyros "cheese" (see tyrosine); but this might be a folk etymology of a Scythian word.
The product was used from an early date in India, Iran and northern Europe, but not in ancient Greece and Rome. Herodotus described it (along with cannabis) among the oddities of the Scythians. Butter-knife attested from 1818.
butter (v.)
Old English buterian "spread butter on," from the same source as butter (n.). Figurative meaning "to flatter lavishly" is by 1798 (with up (adv.), in Connelly's Spanish-English dictionary, p.413). Related: Buttered; buttering.