CATHETUS
, in Geometry, a name by which the perpendicular leg of a right-angled triangle is sometimes called. Or it is in general any line or radius falling perpendicularly on another line, or surface.
Cathetus of Incidence; in Catoptrics, is a right line drawn from a radiant point, or point of incidence, perpendicular to the reflecting line, or plane of the speculum.
Cathetus of Reflection, or of the Eye, a right line drawn from the eye, perpendicular to the plane of reflection.
Cathetus, in Architecture, denotes the axis of a column &c. In the Ionic Capital, it denotes a line passing perpendicularly through the eye or centre of the volute.
