The Collaborative International Dictionary of English v.0.48:

Cretic \Cre"tic\ (kr[=e]"t[i^]k), n. [L. Creticus (sc. pes
   foot), Gr. Kritiko`s (sc. poy`s foot), prop., a Cretan
   (metrical) foot.] (Gr. & Lat. Pros.)
   A poetic foot, composed of one short syllable between two
   long ones (- [crescent] -). --Bentley.
   [1913 Webster]