1. any situation involving contact between two or more minimal groups, as when a group of individuals disembarking from a bus mingles with a group of individuals getting on the bus.

2. a research procedure, used mainly in studies of intergroup conflict, that involves creating temporary groupings of anonymous people whose interdependence is virtually nil. Also called minimal group paradigm. [developed by Polish-born British social psychologist Henri Tajfel (1919–1982)]