There are two kinds of parallelism:
The main task is splitted into smaller ones which can be perform independently and simultaneously.
For example: to process a queue of independent elements by taking multiple items at the same time until emptying the queue.
A big dataset can be splitted into smaller parts than can be processed independently and simultaneously.
For example: to process the product between two matrices by computing each element of the new matrix in different process units.
Every process has at least on thread called main thread which is the entry point for the program.
Thread of execution is the smallest sequence of programmed instrunctions that can be managed independently by a scheduler.
