The Collaborative International Dictionary of English v.0.48:

zit \zit\ (z[i^]t), n.
   a pimple. [slang]
   [PJC]

WordNet (r) 3.0 (2006):

zit
    n 1: a small inflamed elevation of the skin; a pustule or
         papule; common symptom in acne [syn: pimple, hickey,
         zit]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ZIT
       interdisziplinaeres forschungsZentrum fuer Informatik und Technik
(org., Uni Paderborn, Germany)