(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 ]