Source : Webster's Revised Unabridged Dictionary (1913)

Phacops \Pha"cops\, n. [NL., fr. Gr. ? a lentil + ?, ?, the
   eye.] (Paleon.)
   A genus of trilobites found in the Silurian and Devonian
   formations. {Phacops bufo} is one of the most common species.