Definition from Wiktionary, the free dictionary
Alteration of breeches (“trousers, pantaloons”) in use since at least the 18th century in Britain and British colonies.
britches (plural only)
- (dialect) Pants, trousers.
2003, Thad Sitton, Harder than hardscrabble: oral recollections of the farming life ..., page 124:
- And Tom Bowles told him, says, "Go up to the store and get you a free pair of britches [on me]." Says, "Them damned old britches you wearing ain't fittin' to wear to town."
- (breeches): knee britches
breeches — see breeches
pants — see pants