Welcome to the latest edition of our new weekly blog series, Marketing Definitions. Each week, we will identify an oft-used term or phrase in the marketing community and break down its use and meaning for the broader population.

Last week’s term that we defined was Click-through Rate.

Today’s Term = SEO

SEO, which stands for Search Engine Optimization, is a common term used by marketers in the digital age. It is a relatively new term, compared to many others. And that’s because search engines themselves are relatively new.

Google was founded in 1998. They essentially invented the modern search engine. And as they grew, it became increasingly important for companies who wanted to drive traffic to their website to look to Google for answers.

People would start their web sessions on Google, or Yahoo, or some other search engine. They would type in what they were looking for, and the search engine would suggest sites and pages for them to visit.

And so SEO developed as a tool that companies could use to help their websites show up higher in those search rankings. The exact definition of search engine optimization 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.

Over the years, the practice has changed and evolved to meet stricter standards of conduct. As Google and other search engines change their formulas, companies and SEO firms must adapt. But at its core, SEO is about making sure Google knows what your website is all about so that it can show it to people searching for something you offer.

SEO is critical because companies that master it take advantage of huge amounts of “free” traffic, instead of paying to place ads and drive traffic that way.