Definition of sub-debutante in US English:

sub-debutante

noun

US
  • A young woman approaching the age at which she may formally be presented to society at a ball or similar social occasion; a girl in her mid-to-late teens.

Origin

Late 19th century; earliest use found in The Los Angeles Times. From sub- + débutante.

Pronunciation

sub-debutante

/ˌsʌbˈdɛbjʊtɑːnt/