Axilla

The armpit (or axilla) is the area on the human body directly under the area where the arm connects to the shoulder. Hair usually grows in the armpits of both males and females beginning in adolescence, though it is the norm in Western society for females to remove it. Also, armpits develop body odor; for this, there is a wide variety of commercial deodorant and antiperspirant products. Excess armpit odour is known as BO.