Fetching details from the dictionary...

(another's) son; boy; young master
green young man from a well-to-do family; young man innocent of the ways of the world
お坊っちゃんはどこに行かれましたか。
Where did the young master go?
彼は坊っちゃん育ちで世間知らずだ。
He was raised pampered and doesn't know the world.
坊っちゃんという小説を読んだことがある。
I have read the novel called Botchan.