Birthmark/ˈbɜːrθmɑːrk/ Definition 1 of 2Pro Tip 1/3Unique Identity A birthmark is often considered unique to a person, like a fingerprint. His birthmark was so distinctive that it was an instant identifier. Pro Tip 2/3Common Misconception Not all dark spots are birthmarks; some develop later in life. She thought it was a birthmark, but the doctor said it appeared recently. Pro Tip 3/3Neutral Term Birthmark is a neutral term, it doesn't imply beauty or ugliness. The birthmark on her arm was neither admired nor disliked.