from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
RES INTER ALIOS ACTA, evidence. This is a technical phrase which signifies
acts of others, or transactions between others.
2. Neither the declarations nor any other acts of those who are mere
strangers, or, as it is usually termed, any res inter alios ada, are
admissible in evidence against any one when the party against whom such acts
are offered in evidence, was privy to the act, the objection ceases; it is
no longer res inter alios. 1 Stark Ev. 52; 3 Id 1300.