Noun
training bra (plural training bras)
A type of bra used by girls, usually teenage girls when their busts are still small.
When the child is twelve, your wife buys her a splendidly silly article of clothing called a training bra. To train what I never had a training jock. And believe me, when I played football, I could have used a training jock more than any twelve-year-old needs a training bra. Bill Cosby