hip (n.1) Look up hip at Dictionary.com
"part of the human body where pelvis and thigh join," Old English hype "hip," from Proto-Germanic *hupiz (cognates: 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.
hip (n.2) Look up hip at Dictionary.com
"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- (cognates: dialectal Norwegian hjupa, Old Saxon hiopo, Dutch joop, Old High German hiafo, dialectal German Hiefe, Old English hiopa "briar, bramble"), of unknown origin.
hip (adj.) Look up hip at Dictionary.com
"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.
hip (interj.) Look up hip at Dictionary.com
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).