From The Collaborative International Dictionary of English v.0.48:
hep \hep\ (h[e^]p), n. See Hip, the fruit of the dog-rose. [1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
hep \hep\ (h[e^]p), a. Same as Hip, a., but older and now less frequently used. [PJC]
From The Collaborative International Dictionary of English v.0.48:
hep \hep\ (h[e^]p), interj. A call used by drill instructors to count cadence during marching; used identically to hut and hup. [PJC]
From The Collaborative International Dictionary of English v.0.48:
hip \hip\, a. 1. Aware of the latest ideas, trends, fashions, and developments in popular music and entertainment culture; not square; -- same as hep.
Syn: tuned in. [PJC]
2. Aware of the latest fashions and behaving as expected socially, especially in clothing style and musical taste; exhibiting an air of casual sophistication; cool; with it; -- used mostly among young people in the teens to twenties. [PJC]
From The Collaborative International Dictionary of English v.0.48:
Hip \Hip\, n. [OE. hepe, AS. he['o]pe; cf. OHG. hiufo a bramble bush.] (Bot.) The fruit of a rosebush, especially of the English dog-rose (Rosa canina); called also rose hip. [Written also hop, hep.] [1913 Webster]
Hip tree (Bot.), the dog-rose. [1913 Webster]