The Collaborative International Dictionary of English v.0.48:

Tomium \To"mi*um\ (t[=o]"m[i^]*[u^]m), n.; pl. Tomia
   (t[=o]"m[i^]*[.a]) [NL., fr. Gr. te`mnein to cut.] (Zool.)
   The cutting edge of the bill of a bird.
   [1913 Webster]