cube vs square block

cube and square block both are nouns.

Word	Noun	Adjective	Verb	Adverb
cube	Yes	No	Yes	No
square block	Yes	No	No	No

As nouns, cube and square block are synonyms defined as:

cube (noun)	square block (noun)
a block in the (approximate) shape of a cube	a block in the (approximate) shape of a cube
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
the product of three equal terms
a hexahedron with six equal squares as faces
a three-dimensional shape with six square or rectangular sides

cube (verb)	square block (verb)
raise to the third power
cut into cubes