Definition of underarm

The word "underarm" has its origins in Old English. It is derived from two words: "under" meaning "below" and "arm" referring to the upper limb. The phrase "under-earm" or "under-arm" originally referred to the armpit or the area beneath the arm, rather than the actual arm itself. In Middle English, around the 14th century, the phrase underwent a slight change to become "underarm", and eventually, the hyphen was dropped in Modern English, resulting in the single word we use today to describe this body part. So, the next time you use the word "underarm", remember that it has been a part of the English language for centuries, with roots dating back to Old English!