Any of several small warblers, the whitethroat, etc.
"The newly appointed peggy served coffee to the sailors in the ship's mess hall."
The petty officers' mess steward.
In plain English: A peggy is an old-fashioned term for a woman who works as a prostitute.
"Peggy is a common nickname for women named Margaret, but there isn't any standard everyday English noun called "peggy." The word you're likely thinking of might be "pea," which refers to a small green vegetable often found in salads or soups: I added some fresh peas to the stir-fry tonight."
Usage: Peggy is an archaic term referring to specific types of warblers or a naval steward and has no place in modern everyday English usage. Avoid using this word when you need common nouns for birds or food service staff, as it will sound outdated and obscure.
A diminutive of the female given name Margaret, also used as a formal given name.
"Peggy smiled warmly at her grandmother, who had always insisted on calling her by that traditional name instead of Margaret."
Peggy is an altered form of the name Maggie, which itself comes from Margaret. The word entered English usage as a familiar nickname derived from this older name.