rhomboid

RHOM'BOID, n. [Gr. rhomb, and form.]

1. In geometry, a figure having some resemblance to a rhomb; or a quadrilateral figure whose opposite sides and angles are equal, but which is neither equilateral nor equiangular.

2. a. In anatomy, the rhomboid muscle is a thin, broad and obliquely square fleshy muscle, between the basis of the scapula and the spina dorsi.