Longman Dictionary of Contemporary English
Wiktionary
n. A demographic grouping based on age, a generation.
WordNet
n. a group people having approximately the same age [syn: age bracket, cohort]
Usage examples of "age group".
As a matter of fact there is, so far as my observations go, a certain age group that is not content -- these are the young people roughly between seventeen and twenty.
He did his best and even acquired facility in the half-insulting small talk of his age group.
The Householding naturally chose the most competent teacher for this critical age group, so it came as no surprise when he recognized the pregnant woman as Klyd's wife, Yenava.
At home in Cardiff I had been semi-finalist in my age group, before Father brought me to Academy at thirteen.
He was frank enough to say that he wanted no part of it, had viewed his call-up in his age group with distaste, but as there was a job to do -- well, the best thing was to get on with it and get it over.