Quick answer
Mabel is a girl name.
Meaning and history
Medieval form of Amabilis. This spelling and Amabel were common during the Middle Ages, though they became rare after the 15th century. It was revived in the 19th century, perhaps aided by the publication of C. M. Yonge's popular 1853 novel The Heir of Redclyffe, which featured a minor character named Mabel (as well as one named Amabel).
Notes and context
Usage: english