What is the difference between a page and thread? "Each process that is executed is divided into blocks of same size, called pages."
"Thread is a part of process being executed."

Are pages and threads both part(s) of process? Whats the difference between thread as a part of process and page as a part of process?
You're looking at very vague descriptions and asking "What's the difference between these things that haven't been described properly?" For a more detailed understanding, you should, well, look for more detail, which is widely available.

A page is a block of memory; a thread is a sequence of instructions to be executed.