deltoid (deltoid)

and n. [F. del toïde = Sp. deltóide = Pg. It. deltoide, A visit to the shore showed its mouth to be deltoid in character, three mouths being noticed, and probably more existing. Science, III. 706. Specifically- ( a ) In an at.: (1) Forming a triangular place or part; being triangular: as, the deltoid muscle. (2) Relating to the deltoid muscle: as, the deltoid crest of the humerus. (b) In entom., pertaining to or resembling the pyralid moths, or Del to ides. (c) In bot., triangular or trowel-shaped: as, a deltoid leaf: also applied to the cro -section of a leaf, etc. Deltoid moth, a popular name given to various species of the lepidopterous family Pyralidæ, which in repose spread their wings over the back in the form of a triangle. Deltoid Leaf. deltoid II. n. The large, coarse-fibered, triangular muscle of the shoulder, covering and protecting the joint, arising from the spine of the scapula, the acromion, and the clavicle, and inserted into the deltoid crest of the humerus. Its action raises the arm away from the side of the body. See cut under muscle .