noun
son and heir; son who will succeed one
Refers to a son who is expected to inherit the family estate, business, or role. Often used in traditional family contexts.
彼は老舗旅館の跡取り息子だ。
He is the son and heir of a long-established inn.
跡取り息子として、小さい頃から家業を手伝
As the son who will succeed the family business, he has been helping out since he was little.