Source : Webster's Revised Unabridged Dictionary (1913)

Hep \Hep\, n.
   See {Hip}, the fruit of the dog-rose.

Source : WordNet®

hep
     adj : informed about the latest trends [syn: {hip}, {hip to(p)}]
     [also: {heppest}, {hepper}]

Source : Free On-Line Dictionary of Computing

HEP
     
        High Energy (Particle) Physics.