WordNet sense 1 (a hexahedron with six equal squares as faces):

regular hexahedron

WordNet sense 2 (a three-dimensional shape with six square or rectangular sides):

block

WordNet sense 3 (the product of three equal terms):

third power

WordNet sense 4 (a block in the (approximate) shape of a cube):

square block

WordNet sense 5 (cut into cubes):

dice