How to distinguish a process from a thread in an operating system?

A process is an instance of a program that contains its own address space, resources, and state. A thread of execution is a unit of execution within a process that shares the process's address space.

Main differences:

• A process has separate memory, while threads within a process share this memory.
• Processes are isolated from each other, whereas threads within the same process can interact directly.
• Creating a process is more resource-intensive than creating a thread.

Example: a web browser program (process) is running in the OS, and it may have several threads — for rendering, data loading, and user interface.