You may hear the term "SEO" used when someone is referring to any form of online marketing. This is common misconception that can lead to inaccurate and costly differences in expectations vs results.

The real definition of SEO, which stands for "Search Engine Optimization", is the process of getting web pages to show higher in search engine result pages (SERPs) based the search engine's organic algorithm. 

For example, Google has spots for paid ad search results and lower on the page it has spots for "free" search results. Those "free" results were gained via SEO. Where as the paid results, skip the line and show above the "free" results.

Even though organic results are "free" in the sense that you don't pay the search engine (Google) directly, they do take someone, either your own team or outsourced labor, tons of hours and energy to constantly improve and maintain those rankings. Those labor hours do result in most businesses paying someone several thousands of dollars per month.

It's also worth noting that Google is showing organic or "free" results lower and lower, and are favoring businesses willing to pay Google for the top stops. These days Google pushes organic web page results below two entire sections of ads and below the map section, which also includes ads. So, most searchers need to scroll 40% - 60% down the first page of Google before they ever start to see the top organic ranking web page result.