[noun] the act of intervening (as to mediate a dispute) Synonyms: intercession
[noun] a policy of intervening in the affairs of other countries Synonyms: interference
[noun] (law) a proceeding that permits a person to enter into a lawsuit already in progress; admission of person not an original party to the suit so that person can protect some right or interest that is allegedly affected by the proceedings; "the purpose of intervention is to prevent unnecessary duplication of lawsuits"
