The Collaborative International Dictionary of English v.0.48:

Caesarean \C[ae]*sa"re*an\, Caesarian \C[ae]*sa"ri*an\
   (s[-e]*z[=a]"r[i^]*an), a. [L. Caesareus, Caesarianus.]
   Of or pertaining to C[ae]sar or the C[ae]sars; imperial.
   [1913 Webster]

WordNet (r) 3.0 (2006):

caesarian
    adj 1: relating to abdominal delivery [syn: cesarean,
           cesarian, caesarean, caesarian]
    2: of or relating to or in the manner of Julius Caesar [syn:
       Caesarian, Caesarean]
    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]