Keyword research is a practice used by search engine optimization professionals to find and research actual search terms people enter into the search engines when conducting a search. wikipedia.org

Search engine optimization (SEO) is the process of improving the visibility of a website or a web page in search engines via the "natural" or un-paid ("organic" or "algorithmic") search results. wikipedia.org

An SEO audit is an assessment to determine whether or not adjustments need to be made to a site from SEO perspective.

Google AdWords is Google's main advertising product and main source of revenue. wikipedia.org

Display advertising is a type of advertising that typically contains text (i.e., copy), logos, photographs or other images, location maps, and similar items. wikipedia.org

Search engine marketing, (SEM), is a form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages (SERPs) through the use of paid placement, contextual advertising, and paid inclusion. wikipedia.org

Digital marketing is an umbrella term for the marketing of products or services using digital technologies, mainly on the Internet, but also including mobile phones, display advertising, and any other digital medium. wikipedia.org