What is "res inter alios acta"

n. (context legal English) A thing done between others (such as a contract), which cannot adversely affect the rights of those who are not party to it.

Res inter alios acta, aliis nec nocet nec prodest (Latin for "a thing done between others does not harm or benefit others") is a law doctrine which holds that a contract cannot adversely affect the rights of one who is not a party to the contract.

"Res inter alios" has a common meaning: "A matter between others is not our business."