noun
eldest son and heir
Refers specifically to the eldest son who is the heir to the family, often in a traditional or business context. Carries a nuance of responsibility and succession.
彼は老舗旅館の総領息子として育てられた。
He was raised as the eldest son and heir of a long-established inn.
長男 simply means 'eldest son' in a family, without the connotation of being the heir or successor. 総領息子 emphasizes the role of inheriting the family business or estate.
Compound of 総領 (そうりょう, 'overall control; eldest child and heir') and 息子 (むすこ, 'son'). The term is used in traditional family and business contexts.