Definition of tweenager in English:

tweenager

noun

informal
  • A child between the ages of about 10 and 14.

    • ‘The most dangerous toy I encountered as a tweenager was my cousin's new pogo stick.’
    • ‘Apparently tweenagers - 10-13-year-olds - are masters of pester power.’
    • ‘As you can see, the choice of shares for tweenagers is bounded only by your child's personal interests.’

Pronunciation:

tweenager

/ˈtwiːneɪdʒə/