Wikipedia Version:

Search engine optimization (SEO) is the process of affecting the visibility of a website or a web page in a search engine’s unpaid results—often referred to as “natural,” “organic,” or “earned” results. In general, the earlier (or higher ranked on the search results page), and more frequently a site appears in the search results list, the more visitors it will receive from the search engine’s users. SEO may target different kinds of search, including image search, local search, video search, academic search,[1] news search and industry-specific vertical search engines.

Basic English Version:

People don’t want to sort through garbage results when searching for something of interest. So by optimizing your website to be very topic specific, search engines, such as Google, will be able to serve up the exact request. Search Engines like this and give you a more favorable rating for helping them to do a better job. Make sense so far?

Le’s look at an example.
You’re searching for a rug and if you search Google for that term you’ll get:

  • Rug – 125,000,000 results results
  • Target Rug – 8,170,000 results
  • Purple target rug – 743,000 results
  • Target purple leopard rug – 285,000 results
  • Target purple leopard rug 2×3 – 76,400 results

So you get the idea. If a company selling rugs posted a webpage stating that they had the finest assortment of rugs in town with over 10,000 to choose from…they would find themselves in the first search group along with 125 million other pages. The better and more specific your descriptions and headings are, the better the results will be for your potential visitors and therefore the better ranking position from Google and other search engines. There are several plugins that will assist you in obtaining more positive results. One favored plugin for WordPress SEO is Yoast SEO and it’s a free plugin!

Obviously, SEO is a very complex and ever changing subject. However, by keeping  up with the current demands of the search engines, companies like Yoast SEO make it very simple for basic WordPress users to benefit without having to spend a lot of time researching various new changes.