(dated) underwear; undergarments.

(Australia, humorous) A rabbit, or rabbit meat.

(intransitive, especially of an animal, chiefly Canada, US) To escape into a burrow, hole, etc. when being hunted.

(music) A genre of psychedelic alternative rock mostly associated with California in the 1980s.

(idiomatic) A weak spot; a soft spot.

plural of underlying form

(topology) A set of "points" upon which a topology is built, thereby yielding a topological space. / (algebra) A set upon which some operations are defined, thereby yielding an algebraic structure.

Synonym of under one's breath

Any of various central heating (and sometimes cooling) systems which achieves indoor climate control for thermal comfort using conduction, radiation and convection.

(category theory) a forgetful functor