directrix: Meaning and Definition of

di•rec•trix

Pronunciation: (di-rek'triks, dī-), [key]
— pl. di•rec•trix•es, di•rec•tri•ces
  1. a fixed line used in the description of a curve or surface. See diag. under
  2. a directress.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.