Base of a conic solid
The planar region that forms the widest point of a conic solid; often labeled as the 'bottom' of the conic solid, it determines the exact shape of the conic solid.

Cone
It is a 3-D figure with circular base, a vertex not in the plane of the circle, and has a curved surface connecting the base with the vertex. The altitude of the cone is the perpendicular segment that goes from the vertex to the plane containing the circle at the base. The height is the length of the altitude. The slant height is the length of the distance from the vertex to the edge of the base. For a right cone it is necessary that the altitude contains the center of the circle at the base.

Conic solid
The set of points between a point (the vertex) and a non-coplanar region (the base), including the point and the region.

Diameter of a circle (or sphere)
The segment whose endpoints are points on a circle (or sphere) that contains the center of the circle as its midpoint; the length of that segment.

L.A.
Lateral area.

Lateral area
The area of the lateral surface of a solid.
 

Lateral surface
The surface not included in the base (s).   

Right cone
A cone whose axis is perpendicular to the plane containing its base.

Slant height
The length of a lateral edge of a conic solid

Solid
The union of the surface and the region of space enclosed by a 3-D figure; examples: conic solid, cylindrical solid, rectangular solid.

Solid geometry
The study of figures in three-dimensional space.

Space
The set of all possible points; made up of infinite planes.

 Surface
The boundary of a 3-D figure.

Surface area
The total area of the surface of a solid.

Unit cube
Unit of measuring volume.