What is "nonagesimal"

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

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.

a. Of or relating to the ninetieth degree or to a nonagesimal. n. (context astronomy English) The middle to highest point of a part of an ecliptic that is above the horizon at any period of time.