Why are threads called lightweight processes?

Question

A thread is \"lightweight\" because most of the overhead has already been accomplished through the creation of its process.

I found this in one of the tutorials.

Answer 1

process:

1. process id
2. environment
3. folder
4. registers
5. stack
6. heap
7. file descriptor
8. shared libraries
9. instruments of interprocess communications (pipes, semaphores, queues, shared memory, etc.)
10. specific OS sources

thread:

1. stack
2. registers
3. attributes (for sheduler, like priority, policy, etc.)
4. specific thread data
5. specific OS sources