\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.