apsidal

from WordNet (r) 3.0 (2006)

apsidal
    adj 1: of or relating to an apse

from The Collaborative International Dictionary of English v.0.48

Apsidal \Ap"si*dal\ ([a^]p"s[i^]*dal), a.
   1. (Astron.) Of or pertaining to the apsides of an orbit.
      [1913 Webster]

   2. (Arch.) Of or pertaining to the apse of a church; as, the
      apsidal termination of the chancel.
      [1913 Webster]