The Collaborative International Dictionary of English v.0.48:

C-section \C-section\ n.
   contraction of caesarean section.

   Syn: cesarean section, cesarian section,, cesarean, cesarian,
        caesarean.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

C-section
    n 1: the delivery of a fetus by surgical incision through the
         abdominal wall and uterus (from the belief that Julius
         Caesar was born that way) [syn: cesarean delivery,
         caesarean delivery, caesarian delivery, cesarean
         section, cesarian section, caesarean section,
         caesarian section, C-section, cesarean, cesarian,
         caesarean, caesarian, abdominal delivery]