"part of the human body where pelvis and thigh join," Old English hype "hip," from Proto-Germanic *hupiz (source also of Dutch heup, Old High German huf, German Hüfte, Swedish höft, Gothic hups "hip"), of uncertain origin. In architecture, "external angle at the junction of two sides of a roof," from late 17c. Hip-flask, one meant to fit in a hip pocket, is from 1923. Related: Hips.
"seed pod" (especially of wild rose), a 16c. alteration of Middle English hepe, from Old English heope, hiope "seed vessel of the wild rose," from Proto-Germanic *hiup- (source also of dialectal Norwegian hjupa, Old Saxon hiopo, Dutch joop, Old High German hiafo, dialectal German Hiefe, Old English hiopa "briar, bramble"), of unknown origin.
"informed," 1904, apparently originally in African-American vernacular, probably a variant of hep (1), with which it is identical in sense, though it is recorded four years earlier.
exclamation used to introduce a united cheer (as in hip-hip-hurrah), 1827, earlier hep; compare German hepp, to animals a cry to attack game, to mobs a cry to attack Jews (see hep (2)); perhaps a natural sound (such as Latin eho, heus).