Meaning of proctodeum

proc•to•de•um

Pronunciation: (prok"tu-dē'um), [key]
— pl. -de•a -de•ums.
  1. a depression in the ectoderm of the anal region of a young embryo, which develops into part of the anal canal.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.