Overview
Tomboy is a term used for girls or young women with masculine traits. It can include wearing androgynous or unfeminine clothing and engaging in physical sports or other activities and behaviors usually associated with boys or men.
Origins
The word "tomboy" is a compound word which combines "tom" with "boy". Though this word is now used to refer to "boy-like girls", the etymology suggests the meaning of tomboy has changed drastically over time.
In 1533, according to the Oxford Dictionary of English, "tomboy" was used to mean a "rude, boisterous or forward boy". By the 1570s, however, "tomboy” had taken on the meaning of a "a bold or immodest woman", finally, in the late 1590s and early 1600s, the term morphed into its current meaning: "a girl who behaves like a spirited or boisterous boy; a wild romping girl."
History
From Wikipedia (CC BY-SA 4.0).