1. (a.) Acting in conjunction; occurring simultaneously or side by side; meeting at one point\.

2. (a.) Conjoined; associate; concomitant; existing or happening at the same time.

3. (a.) Joint and equal in authority; taking cognizance of similar questions; operating on the same objects; as, the concurrent jurisdiction of courts.

4. (a.) Meeting in one point.

5. (n.) One who, or that which, concurs; a joint or contributory cause.

6. (n.) One pursuing the same course, or seeking the same objects; hence, a rival; an opponent.

7. (n.) One of the supernumerary days of the year over fifty-two complete weeks; -- so called because they concur with the solar cycle, the course of which they follow.

accessory accompanying accordant agreeing aligned analogous approaching associate associated asymptotic at one at one with attendant attending carried by acclamation centripetal centrolineal coacting coactive coadjutant coadjuvant coadunate coefficient coetaneous coeternal coeval coexistent coexisting coextending coextensive coincident coinstantaneous collaborative collateral collective collectivist collectivistic collusive combined combining commensal common communal communalist communalistic communist communistic communitarian compact comprehensive concerted concomitant concordant concurring confluent confocal conjoint conjugate conjunct connivent conniving consentaneous consilient conspiratorial contemporaneous contemporary conterminous converging cooperant cooperating cooperative coordinate corporate correlative coterminous coupled coworking ecumenic equal equidistant equispaced even fellow focal harmonious harmonized in agreement inclusive isochronal isochronous joined joint like-minded lined up meeting mutual mutually approaching noncompetitive nonconvergent nondivergent of a piece of one accord of one mind paired parallel parallelepipedal parallelinervate paralleling parallelodrome parallelogrammatic parallelogrammic parallelotropic parasitic radial radiating reciprocal saprophytic simultaneous solid symbiotic synchronal synchronic synchronous synergetic synergic synergistic tangent tangential twin unanimous unchallenged uncompetitive uncontested uncontradicted uncontroverted unison unisonous united uniting unopposed with one consent with one voice