Origin: Germanic Old English prefix
Betty has 2 different meanings across 1 category:
An attractive woman; a babe.
"The gang was out looking for betties at the summer dance."
In plain English: Betty is an old-fashioned name for a woman, often used to describe someone who acts silly or foolishly.
"The neighbors always had their famous Betty cake for Sunday brunch."
A diminutive of the female given name Elizabeth.
"Betty smiled warmly at her grandmother, who had always called her by that affectionate nickname instead of Elizabeth."
The name "betty" originally came from Elizabeth, but thieves' cant used similar nicknames like Bess for tools used to wrench locked doors. Its modern meaning as a term for an attractive woman likely stems from the popular character Betty Rubble in The Flintstones.