noun
Legal and general term for a person who inherits property, rights, or obligations. 相続人 is neutral and commonly used in inheritance contexts.
彼は父親の遺産の相続人だ。
He is the heir to his father's estate.
法定相続人には配
Statutory heirs include the spouse and children.
相続 is the act or process of inheritance; 相続人 is the person who performs that act.
Compound of 相続 (inheritance) + 人 (person). The exact historical derivation is straightforward; the word is a standard Sino-Japanese legal term.