Dictionary

The fraction of incident light or radiation reflected by a surface or body, commonly expressed as a percentage.

The whitish inner portion of the rind of citrus fruits that is a source of pectin, commonly referred to as the pith.

One of the four major stages of the magnum opus, involving purification of the prima materia.

(common usage) Sexual urges or drives.

Example: Good grief man, control your libido!

Drives or mental energies related to or based on sexual instincts but not necessarily sexual in and of themselves.

Example: For Freudians, libido means the desire to "unite and bind" with objects in the world.