(SEO) or in other words, Search Engine Optimization. The objective here is to increase your website's traffic, and ultimately convert that traffic into some kind of goal you have set for your website. The goal you have set being met is also known as a conversion. Often that is a sale of some kind. However, you might be trying to attract new members, get donations, inform the public of an important issue, etc. In all cases what is called a "conversion" is met when you achieve the goal you have set for the website.
Optimizing your website results in ranking very high in searches results for keywords that you want your website to be listed in. More specifically well done search engine optimization positions your website rank higher than it's competitors in certain searches or at the very least on the same page. This is often accomplished by re-working, very often by re-writing the content of your website to be more relevant than your competitors in certain search queries.
Search engine optimization is often thought to be an effort to rank top choice for every single keyword or search term you have for your website. That isn't the case. The effort here is to rank high in many keywords and search terms. You can't always be at the top of all search results. That would be an unrealistic goal at best. Being realistic, you can rank very high in many searches relevant to you. Sometimes you will be number one, not always. I am going to explain each area of website or web page optimization a little in order to help you understand the basic concepts behind Search Engine Webpage Optimization.