SEO keywords play a pivotal role in enhancing your visibility online. However, let's delve deeper and understand, what exactly is a keyword in SEO.

In internet marketing, a keyword is a particular term or expression that people type into search engines when they are searching for a unique service, product or information. Search engine optimization (SEO) heavily relies on the use of these keywords in ranking websites.

The magic behind SEO keywords lies in their ability to associate what users are searching for to the content that you’re offering on your website. Effectively using these keywords will help draw the right audience and boost the likelihood of sales.

Having established the definition of an SEO keyword, let's look at methods for efficiently using keywords. Optimizing the use of keywords requires a balance. You'd want to include relevant keywords to appeal to search algorithms but without overloading your content with them.

One way is placing the keyword in your content’s headline. This not only helps in ranking, but also makes your content more relevant to the searcher's query. Consider also using keywords in the meta description and headings of your website, as these are points where search engines tend to look.

Additionally, it's important to choose keywords that resonate with your target market. It means understanding their language, their search behaviors and their requirements.

In conclusion, a well-chosen SEO keyword can serve as a link between what a person is looking for and the service or information you provide. It's a critical tool to be successful in the cut-throat world of what is an SEO keyword digital marketing. However, as with all tools, using it correctly is the key to unlocking its full potential.