fem. pet name, from Bet, shortened from Elizabeth, + -y (3). Also in old slang (by 1857), "man who interferes with the domestic duties of women" [Century Dictionary, 1889].
better
betterment
bettermost
betting
bettor
Betty
Betula
between
betweenity
betweenness
betwixt
)window.location='https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=byronic106@yahoo.com&lc=US&item_name=Donation+to +Help+Keep+Etymonline+Free+and+Open&no_note=0&cn=&curency_code=USD&bn=PP-DonationsBF:btn_donateCC_LG.gif:NonHosted'){kind=link}