Medical Dictionary

1deltoid

noun del·toid \ˈdel-ˌtid\

Medical Definition of DELTOID

:  a large triangular muscle that covers the shoulder joint, serves to raise the arm laterally, arises from the upper anterior part of the outer third of the clavicle and from the acromion and spine of the scapula, and is inserted into the outer side of the middle of the shaft of the humerus—called also deltoid muscle; see deltoid tuberosity

Illustration of DELTOID

How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears