betweenager vs preteen

betweenager

noun
  • Synonym of tweenager 

preteen

noun
  • A child between approximately 10 and 12 years of age, at the onset of adolescence. 

adj
  • Of, relating to, or designed for, or being children between the ages of approximately 10 and 12. 

How often have the words betweenager and preteen occurred in a corpus of books? (source: Google Ngram Viewer )