girl

1250–1300; Middle English gurle, girle, gerle child, young person; compare Old English gyrela, gi(e)rela, item of dress, apparel (presumably worn by the young in late OE period, and hence used as a metonym)

Some adult women are offended if referred to as a girl, or informally, a gal. However, a group of adult female friends often refer to themselves as the girls, and their “girls night out” implies the company of adult females. Also, a woman may express camaraderie by addressing another woman as girl, as in You go, girl! or Attagirl!
Referring to one's female office assistant or housekeeper as the girl or my girl, once in common use, is now considered unacceptable. Working girl, meaning “a woman who works,” girl/gal Friday, meaning “a female office assistant,” and other occupational terms such as career girl and college girl, are also dated and often perceived as insulting. Working girl as a slang term meaning “a prostitute” is sometimes used by female prostitutes as a euphemistic self-reference. See also lady, woman.