Douglas Harper's Etymology Dictionary
Wiktionary
n. A person who is between 10-12 years of age and is about to enter their teenage years.
Usage examples of "pre-teen".
The chariot has been halted in the act of bearing down on Diomedes, all the human players here unaware that the goddess Athena has stopped everything while she plays dolls with her chosen champion, dressing Diomedes in forcefields and thru-view contact lenses and nano-augmenters like some pre-teen girl playing with her Barbie.
Later, as we got more popular, Esther brought her oldest daughter, who was still a pre-teen, to sing in the show.
Thus we are beginning to form not only a college student ghetto, but even semi-ghettos of pre-teens and teenagers, each with its own peculiar tribal characteristics, its own fads, fashions, heroes and villains.
The hospital emergency suite has a waiting room with green plastic bucket seats and subtractive volume renderings by pre-teens stuck to the walls like surreal Lego sculptures.
These would have to be very closely watched as they were manned by relatively inexperienced sailors—many of them pre-teens — who had been assigned the unusual duty.