The Collaborative International Dictionary of English v.0.48:

Cuboid \Cu"boid\ (k?"boid), a. [Cube + -oid: cf. Gr. ???.]
   (Anat.)
   Cube-shaped, or nearly so; as, the cuboid bone of the foot.
   -- n. (Anat.) The bone of the tarsus, which, in man and most
   mammals, supports the metatarsals of the fourth and fifth
   toes.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cuboid
    adj 1: shaped like a cube [syn: cubelike, cube-shaped,
           cubical, cubiform, cuboid, cuboidal]
    n 1: a rectangular parallelepiped