What is the difference between a queue and a thread?

Queue — an abstraction for managing tasks that need to be executed. It defines the order in which these tasks are executed (sequentially or in parallel) and on which thread.

Thread — a unit of parallel code execution in the operating system. Queues use threads for the physical execution of tasks.

Main differences:

Aspect	Queue	Thread
Purpose	Managing task order	Unit of code execution
Abstraction	High-level, task management	Low-level, OS resource
Creation	Less costly	More costly, requires OS resources
Management	Dispatch Queues, Operation Queues	POSIX Threads, NSThread, DispatchQueue manages them internally
Dependency	Uses threads for execution	Executes code