/verr"teks/ , n. , pl. vertexes, vertices /-teuh seez'/ .
1. the highest point of something; apex; summit; top: the vertex of a mountain.
2. Anat. , Zool. the crown or top of the head.
3. Craniom. the highest point on the midsagittal plane of the skull or head viewed from the left side when the skull or head is in the Frankfurt horizontal.
4. Astron. a point in the celestial sphere toward which or from which the common motion of a group of stars is directed.
5. Geom.
a. the point farthest from the base: the vertex of a cone or of a pyramid.
b. a point in a geometrical solid common to three or more sides.
c. the intersection of two sides of a plane figure.
[ 1560-70; vert ( ere ) to turn + -ex (s. -ic- ) n. suffix ]