Meaning of cathetus

cath•e•tus

Pronunciation: (kath'i-tus, ku-thē'tus), [key]
— pl. -ti
  1. (in an Ionic capital) the vertical guideline through the eye of a volute, from which the form of the volute is determined.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.