deltoid       
 noun [ C ]  anatomy specialized uk/ˈdel.tɔɪd/ us/ˈdel.tɔɪd/ (also deltoid muscle)
 (肩上的)三角肌
a muscle in the shoulder, shaped like a triangle and used for lifting the arm
  Always stretch your deltoids after lifting weights. 提举重物以后一定要舒展一下三角肌。 
 The deltoid muscle lifts the arm sideways. 三角肌使手臂能够侧举。 
 deltoid       
adjective  anatomy specialized uk/ˈdel.tɔɪd/ us/ˈdel.tɔɪd/
 三角形的
shaped like a triangle
  a deltoid ligament 三角韧带