Definition of "boomlet"

This is the twentysomething generation, those 48 million young Americans ages 18 through 29 who fall between the famous baby boomers and the boomlet of children the baby boomers are producing.

1990 July 16, David M. Gross, Sophfronia Scott, “Proceeding With Caution”, in Time‎

There was a boomlet in fitness centers as corporations sweetened their programs to pay for part of their employees' gym memberships […] .

2017, David Friend, The Naughty Nineties