Concurrency
In plain terms
Structuring a program to handle many tasks that overlap in time.
Going deeper
Concurrency is about dealing with lots of things at once (interleaving tasks), which may or may not run literally in parallel. It keeps apps responsive but introduces challenges like shared-state coordination and race conditions.
Under the hood
Concurrency (dealing with many things) differs from parallelism (doing many things at once); correctness hinges on managing shared mutable state via locks, atomics, or message passing.
Examples
Web servers handling many requests, async I/O, actor systems (Akka), Go goroutines.
Think of it like...
Like a chef juggling several dishes: chopping while something simmers and bread bakes, switching between them so nothing stalls.