'tweenager

Noun

tweenager (plural tweenagers)

1. A young person who is not yet a teenager (being less than thirteen years old), but starting to act like one: generally ten to twelve years old.
   • Your eight to twelve year old is in the gray area between early childhood and the teen years. He is a child in the middle—a “tweenager.”1994, Mary Manz Simon, How to Parent Your “Tweenager”, page 6

   Synonyms:

   preteen