Deltoids (noun)

1. A muscle in the shoulder that is responsible for moving the arm away from the body.
2. A triangular muscle located on the upper arm, upper back and shoulder blade.

Origin:

Derived from the greek letter delta, referring to the triangular shape of the muscle.

Examples:

1. He felt a burn in his deltoids as he lifted the heavy weights.
2. She worked on strengthening her deltoids to improve her posture.
3. The deltoids are important muscles that help move the arm away from the body.
4. He had a well-defined set of deltoids that gave him a broad shoulders.
5. The deltoids are one of the three muscles that make up the shoulder, the others are the supraspinatus and infraspinatus.