Meaning

noun a hexahedron with six equal squares as faces

noun a three-dimensional shape with six square or rectangular sides

noun the product of three equal terms

originClipped form of cubicle (with intentional reference to their common shape per cube, etymology 1), which from Latin cubiculum (“a small bedchamber or lounge”), from cubare (“to lie down”).

Etymology from Wiktionary, CC BY-SA 3.0