The first part is easy: The three main search engines are Google, Bing and Yahoo. Google is the most popular – after all it’s become a verb in just about every language around the world.
Since it’s called an engine, go ahead and think of Google as a train rushing around the Internet finding all the pages on all the websites on earth. When you own a business you need to prepare your website so Google sees exactly what you’re selling and why it’s so wonderful. And this magic exists in the TEXT that’s written on the pages.
If you think the word optimization is too long and stupid, go ahead and call it Google Prep. SEO simply means preparing your website so Google knows enough about what you do or sell so people can find it when they search.