noun
joint heir; co-heir
Legal term for a person who inherits property together with one or more others. Used in inheritance law contexts.
彼は兄と共同相続人として土地を受け継いだ。
He inherited the land as a joint heir with his older brother.
相続人 is a general heir, while 共同相続人 specifically means a joint heir who shares the inheritance with others.
Compound of 共同 (joint) + 相続人 (heir). A straightforward legal term.