1. The highest point that a celestial body attains.

2. On a great circle, that point that is closest to a pole.

1. For a polygon or polyhedron, any of those finitely many points which together with line segments or plane pieces determine the figure or solid.

2. The common point at which the two sides of an angle intersect.

3. The fixed point through which pass all the elements of a cone or conical surface.

4. An intersection of a conic with one of its axes of symmetry.

One of the points where the surface of a lens intersects the optical axis.