type of trousers, 1882, from bell (n.) + bottom (n.). Distinguished in the late 1960s from flares by the shape of the expanded part (flares straight, bell-bottoms of inverted cup-shape, like a bell).
Entries linking to bell-bottoms
bell n.
"hollow metallic instrument which rings when struck," Old English belle, which has cognates in Middle Dutch belle, Middle Low German belle but is not found elsewhere in Germanic (except as a borrowing); perhaps from an imitative PIE root *bhel- "to sound, roar" (compare Old English bellan "to roar," and see bellow).
As a division of daily time aboard a ship, by 1804, from its being marked by bells struck every half hour. The statistical bell curve is by 1920, said to have been coined 1870s in French. Of glasses in the shape of a bell from 1640s. Bell pepper is from 1707, also so called for its shape. Bell, book, and candle is a reference to a form of excommunication (the bells were rung out of order and all together to signify the loss of grace and order in the soul of the excommunicated).
To ring a bell "awaken a memory" (1934) is perhaps a reference to Pavlovian experiments; it also was a signal to summon a servant (1782).
bottom n.
Middle English botme, from Old English botm, bodan "ground, soil, foundation, lowest or deepest part of anything," from Proto-Germanic *buthm- (source also of Old Frisian boden "soil," Old Norse botn, Dutch bodem, Old High German bodam, German Boden "ground, earth, soil"). This is perhaps from PIE root *bhudhno- "bottom" (source also of Sanskrit budhnah, Avestan buna- "bottom," Greek pythmen "foundation," Latin fundus "bottom, piece of land, farm," Old Irish bond "sole of the foot").
The meaning "fundamental character, essence" is from 1570s; to get to the bottom of some matter is from 1773. The meaning "posterior of a person" (the sitting part) is from 1794. Bottoms up as a call to finish one's drink is from 1875. Bottom dollar "the last dollar one has" is from 1857. To do or feel something from the bottom of (one's) heart is from 1540s. Bottom-feeder, originally in reference to fish, is from 1866.