(n) a large triangular muscle covering the shoulder joint and serving to abduct and flex and extend and rotate the arm, Syn. musculus deltoideus, deltoid muscle
(n) a common poplar of eastern and central United States; cultivated in United States for its rapid growth and luxuriant foliage and in Europe for timber, Syn. necklace poplar, Populus deltoides
a. [ Gr. deltoeidh`s delta- shaped; de`lta the name of the letter Δ + e'i^dos form: cf. F. deltoïde. See Delta. ] 1. Shaped like the Greek Δ (delta); delta-shaped; triangular. [ 1913 Webster ]
Deltoid leaf (Bot.), a leaf in the form of a triangle with the stem inserted at the middle of the base. -- Deltoid muscle (Anat.), a large triangular muscle covering the shoulder joint, which serves to raise the arm directly upward. [ 1913 Webster ]
2. of or pertaining to the deltoid muscle. [ PJC ]