best girl

plural best girls · alternative best gal

1. datedOne's girlfriend.

   […] your fine magazine […] is a pleasure to read anywhere, but in an isolated spot such as this it's almost as good as a sugar report from the best girl!

   1954, Esquire, volume 41, number 2, page 12

   1 more example

   Soon, you might think, a lone figure dressed in tails and a top-hat — Fred Astaire, or maybe Gene Kelly — would appear and dance his way from one of those spots to the next, singing about how lonely a fellow could be when his best girl had given him the air and all the bars were closed.

   1991, Stephen King, Needful Things

2. film productionA woman who performs the duties of a best boy.
3. InternetslanglifestyleA reader or viewer's preferred female character.

   Also: Miku is best girl, thank you for attending this TED Talk.

   2020 April 22, Will Harrison, “15 Anime To Watch If You Love Fruits Basket”, in CBR