Axillae, also known as underarms, refers to the hollow areas beneath the shoulders where the upper arm meets the torso. Synonyms for Axillae include armpits, pit, and axilla. The word axilla is the medical term for these areas. People tend to use these terms interchangeably in everyday communication, and they all refer to the same anatomical feature. Perspiration is a common issue in the axillae, and many people use antiperspirant deodorants to manage this. Keeping the axillae clean and dry is essential to avoid unpleasant odors and skin irritation.