Definition of subteen in English:

subteen

noun

US
  • A child under (especially just under) the age of thirteen; a pre-teen.

adjective

US
  • Of a child: under (especially just under) the age of thirteen; not yet teenage. Of a thing: characteristic of, relating to, or designed for this age group.

Origin

1920s; earliest use found in Portsmouth (Ohio) Daily Times. From sub- + teen.

Pronunciation

subteen

/ˌsʌbˈtiːn/