Cath"e*tus (?), n.; pl. catheti (#). [L., fr. Gr. a perpendicular line, fr. let down, fr. . See Catheter.] Geom.
One line or radius falling perpendicularly on another; as, the catheti of a right-angled triangle, that is, the two sides that include the right angle.
Barlow.
© Webster 1913.