Non`a*ges"i*mal (?), a. [L. nonagesimus the ninetieth. See Nonagenarian.] (Astron.) Of or pertaining to the ninetieth degree or to a nonagesimal.

Non`a*ges"i*mal, n. (Astron.) The middle or highest point of the part of the ecliptic which is at any given moment above the horizon. It is the ninetieth degree of the ecliptic, reckoned from the points in which it is intersected by the horizon.