preteen

[pree-teen]
noun
  1. Also called pre·teen·ag·er [pree-teen-ey-jer] /priˈtinˌeɪ dʒər/, pre·teen·er. a boy or girl under the age of 13, especially one between the ages of 9 and 12.
  2. preteens, the years immediately preceding one's thirteenth birthday.
adjective
  1. designating or characteristic of a preteen or preteens: two preteen daughters.

Origin of preteen

First recorded in 1950–55; pre- + teen2
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for preteen's

preteen

noun
  1. a boy or girl approaching his or her teens
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

preteen's in Medicine

preteen

[prētēn]
adj.
  1. Relating to or designed for children especially between the ages of 10 and 12.
  2. Being a child especially between the ages of 10 and 12; preadolescent.
n.
  1. A preteen boy or girl.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.