In math, a cube is a number multiplied by itself three times. The cube of 2 is 8 (2 x 2 x 2). It is also a threedimensional shape where each of the six sides is a square or something shaped like a cube, such as an ice cube or meat cut into cubes).
The noun cube goes back to the Greek word kybos, which was a sixsided die used in games. As a verb, cube means to cut into cube shapes. You can buy cookie dough that is ready for baking and formed into cubes. Place each cube on the cookie sheet, and the dough becomes a dozen round cookies — or fewer if you pop a cookie dough cube into your mouth before baking!
Primary Meanings of cube
1. 
nv 
a hexahedron with six equal squares as faces
cut into cubes

2. 
nv 
the product of three equal terms
raise to the third power

3. 
n 
any of several tropical American woody plants of the genus Lonchocarpus whose roots are used locally as a fish poison and commercially as a source of rotenone

Full Definitions of cube
1
n a hexahedron with six equal squares as faces
 Synonyms:
 regular hexahedron
 Type of:

Platonic body, Platonic solid, ideal solid, regular convex polyhedron, regular convex solid, regular polyhedron
any one of five solids whose faces are congruent regular polygons and whose polyhedral angles are all congruent
n a threedimensional shape with six square or rectangular sides
n a block in the (approximate) shape of a cube
 Synonyms:
 square block
 Types:
 show 6 types...
 hide 6 types...

dice, die
a small cube with 1 to 6 spots on the six faces; used in gambling to generate random numbers

ice cube
a small cube of artificial ice; used for cooling drinks

five, fivespot
a playing card or a domino or a die whose upward face shows five pips

four, fourspot
a playing card or domino or die whose upward face shows four pips

onespot
a domino or die whose upward face shows one pip

six, sixspot
a playing card or domino or die whose upward face shows six pips
 Type of:

block
a solid piece of something (usually having flat rectangular sides)
2
n the product of three equal terms
 Synonyms:
 third power
 Type of:

number
a concept of quantity involving zero and units