Armpit (noun)

1. The hollow under the joint of the arm and the shoulder where the arm joins the shoulder.
2. A part of a garment that covers the armpit.

Origin:

Late middle english: from middle low german armpit, from arm "arm" + pit "hole".

Examples:

1. She rubbed her armpit and wrinkled her nose at the unpleasant odor.
2. The dress was too tight in the armpits and uncomfortable to wear.
3. He scratched at his armpit and yawned, feeling sleepy and lazy.
4. The armpits of the shirt were stained with sweat, so he changed into a clean one.
5. She raised her arm and sniffed her armpit, relieved to find that she didn't smell too bad.