Source : Webster's Revised Unabridged Dictionary (1913)

Aphotic \A*pho"tic\ ([.a]*f[=o]"t[i^]k), a. [Gr. 'a`fws,
   'a`fwtos.]
   Without light.

Source : WordNet®

aphotic
     adj : lacking light; especially not reached by sunlight; "the
           aphotic depths of the sea where no photosynthesis
           occurs"