1.Concurrency


Definition:
Concurrency is when multiple tasks make progress at the same time, but not necessarily executing at the exact same instant. It’s about dealing with many things at once, often by switching between them quickly.
Think of one chef cooking multiple dishes. The chef chops vegetables for one dish, then stirs the soup for another, then checks the oven—switching tasks fast.
The tasks overlap in time, but the chef is still doing one thing at any given instant.

In programming:
Using threads, async/await, or coroutines.
Example: Downloading multiple files over the internet without waiting for each to finish sequentially.

2.Parallelism

Definition:
Parallelism is when multiple tasks actually run at the same exact time. It requires multiple CPU cores or processors.
Think of multiple chefs in a kitchen, each cooking a different dish simultaneously.
All tasks are truly executing at the same instant.

In programming:
Using multi-core processing or GPU computation.
Example: Processing a huge dataset by splitting it across multiple cores.