When things are concurrent, they happen at the same time. If you're taking three concurrent classes this semester, you're enrolled in all three during the same period. If two movies have concurrent releases, they both come out on the same weekend.

Picture two runners keeping pace side by side on a track: they're running concurrently. In computing, when a program performs concurrent operations, it's handling multiple tasks simultaneously, like when your computer plays music while you type a document.

You'll often hear this word in schedules and systems. A student might serve two concurrent detentions (meaning they overlap in time, not that they happen in sequence). A prisoner might receive concurrent sentences, serving multiple punishments at once rather than one after another. Scientists run concurrent experiments to test different approaches to the same problem at the same time.

The opposite is consecutive, which means one after another. If you read three books concurrently, you're reading all three at once, switching between them. If you read them consecutively, you finish one completely before starting the next.