1. (n.) A meeting or coming together; agreement\; union; conjunction; combination.

2. (n.) A meeting of minds; agreement in opinion; union in design or act; -- implying joint approbation.

3. (n.) Agreement or consent, implying aid or contribution of power or influence; cooperation.

4. (n.) A common right; coincidence of equal powers; as, a concurrence of jurisdiction in two different courts.

acceptance accession acclamation accompaniment accord accordance acquiescence agglomeration agglutination aggregation agreement agreement in principle agreement of all alignment alternation analogy approach articulation assemblage assembly assent assentation asymptote bipartisanship bond bottleneck bracketing call-up canvass census chorus clustering co-occurrence coaction coadjuvancy coadministration coagency cochairmanship codirectorship coetaneity coetaneousness coevalneity coevalness coexistence coextension coincidence collaboration collaborativeness collection collectivism colligation collineation collision course collocation collusion combination commensalism common assent common consent common effort common enterprise communalism communication communism communitarianism community comparison complementary distribution compliance complicity concatenation concentralization concentration concert concomitance concomitancy concord concordance concourse confluence conflux congeries conglomeration congregation congress conjugation conjunction connection consensus consensus gentium consensus of opinion consensus omnium consent consentaneity contemporaneity contemporaneousness convergence converging cooperation cooperativeness copulation corralling coupling crossing data-gathering duet duumvirate ecumenicalism ecumenicism ecumenism engagement equidistance esprit esprit de corps fellow feeling fellowship focalization focus funnel gathering general acclamation general agreement general consent general voice harmony hearty assent hookup hub ingathering interaction interchange intercommunication intercourse interlacing interlinking intermeshing interplay intertwining interweaving interworking inventory isochronism joinder joining joining of forces joint effort joint operation jointure junction juxtaposition knotting liaison like-mindedness linkage linking marriage mass action meeting meeting of minds merger merging mesh meshing mobilization morale muster mutual approach mutual assistance mutual understanding mutualism mutuality narrowing gap nondivergence octet one accord one voice pairing parallelism pooling pooling of resources pulling together quartet quid pro quo quintet radius reciprocity rodeo roundup same mind seesaw septet sextet simultaneity single voice solidarity splice spokes support survey symbiosis synchronism synchronization synergism synergy tangent team spirit teamwork tie tie-in tie-up tit for tat togetherness total agreement trio triumvirate troika unanimity unanimousness understanding unification union unison united action universal agreement warm assent welcome withness yoking