coaction, coadjuvancy, coadministration, coagency, cochairmanship, codirectorship, collaboration, collaborativeness, collectivism, collusion, commensalism, common effort, common enterprise, communalism, communism, communitarianism, community, complicity, concert, concord, concordance, concurrence, cooperation, cooperativeness, duet, duumvirate, ecumenicalism, ecumenicism, ecumenism, esprit, esprit de corps, fellow feeling, fellowship, harmony, joining of forces, joint effort, joint operation, mass action, morale, mutual assistance, mutualism, mutuality, octet, pooling, pooling of resources, pulling together, quartet, quintet, reciprocity, septet, sextet, solidarity, symbiosis, synergism, synergy, team spirit, teamwork, trio, triumvirate, troika, united action