(a.) Happening at the same time; simultaneous.

accompanying accordant according affirmative agreeable agreeing answerable associate associated assonant assonantal at one at one with attuned blended blending chiming coacting coactive coadunate coetaneous coeval coexistent coexisting coherent coincident coinciding collaborative collective collusive combined combining commensurate compatible concerted concomitant concordant concurrent concurring conformable congenial congruent congruous conjoint consentaneous consentient consilient consistent consonant conspiratorial contemporaneous cooperant cooperating cooperative coordinate correspondent corresponding coworking en rapport equivalent harmonic harmonious harmonizing homophonic in accord in agreement in chorus in concert in concord in phase in rapport in step in sync in synchronization in tempo in time in tune in unison inaccordance inharmony joint like-minded meeting monodic monophonic of a piece of like mind of one mind on all fours on the beat parasitic positive proportionate reconcilable saprophytic self-consistent simultaneous symbiotic symphonious synchronal synchronic synchronized synergetic synergic synergistic tuned unanimous uniform unisonant unisonous united uniting