at the same time; at once; just as ...; the moment ...; (but) at the same time; as well as
simultaneous development; spreading at the same time (e.g. two phenomena)
simultaneous interpretation; simultaneous interpreting; simultaneous interpreter
concurrent connections; simultaneous connections
timing is everything; don't jump the gun
simultaneous recording (of image and sound); synchronous recording
polyphony (of an electronic keyboard or synthesizer)
polyphony (of an electronic keyboard or synthesizer)
double election (e.g. of the lower and higher chambers)
occurring at the same time in different places (e.g. terrorist attacks)