The Collaborative International Dictionary of English v.0.48:

Pyla \Py"la\ n.; pl. L. Pyl[ae], E. Pylas. [NL., fr. Gr. ?
   an entrance.] (Anat.)
   The passage between the iter and optoc[oe]le in the brain.
   --B. G. Wilder.
   [1913 Webster]