noun

*pl.*-·tex·es or -·ti·ces·

- the highest point; summit; apex, as the top point of the sun, moon, etc. above the horizon
- the top or crown of the head
- Geom.
- the point of intersection of the two sides of an angle
- a corner point of a triangle, square, cube, parallelepiped, or other geometric figure bounded by lines, planes, or lines and planes

- Optics the point at the center of a lens at which the axis of symmetry intersects the curve of the lens

Origin of vertex

L, the top, the turning point from*vertere,*to turn: see verse