e-book basic questions...

Disclosure: I am a technology idiot when it comes to a lot of the new media. I do not FB, TXT, Tweet. I use the internet for information gathering and interest/ hobbby forums such as RVnet. My electronic communications consist of e-mail and cell phone. I am and old school, fuddyduddy tech-wise.

That said, is the word "e-book" just the basic term meaning "electronic book" and it is not proprietary? Does e-book mean just the basic concept of downloading written words to a receiving device (i.e. computer, laptop, tablet, etc..)

I see the brands Kindle and Nook. Are these just electron versions of a book sellers just like a Barnes & Noble would be for a physical book?

I see where Amazon sells Kindle e-books. I also see where folks have purchased separate pieces of hardware in order to buy e-books. I do not want more electronic devices if I can help it.

Can I purchase from Amazon and read a Kindle e-book on my PC without buying additional items?

I will wait for replies before I ask any more question as the responses might answer still lingering questions I have.

Thanks!
-tr