n 1  :  one of the projecting paired appendages (as an arm, wing, fin, or parapodium) of an animal body made up of diverse tissues (as epithelium, muscle, and bone) derived from two or more germ layers and concerned esp. with movement and grasping but sometimes modified into sensory or sexual organs : esp  :  a human leg or arm  2  :  a branch or arm of something (as an anatomical part) <the descending of Henle's loop>  .
 
 
 
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