rhom·boid / ˈrämˌboid/ • adj. having or resembling the shape of a rhombus.• n. 1. a quadrilateral of which only the opposite sides and angles are equal.2. (also rhom·boid mus·cle) another term for rhomboideus.DERIVATIVES: rhom·boi·dal / rämˈboidl/ adj.

rhomboid

rhomboid (rom-boid) n. either of two muscles situated in the upper part of the back, between the backbone and shoulder blade. They help to move the shoulder blade backwards and upwards.