Search engine marketing (SEM) is a form of internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages through optimization and advertising. SEM may use search engine optimization (SEO), that adjusts or rewrites website content to achieve a higher ranking in search engine results pages or use pay per click listings (Source WikiPedia)
Merriam-Webster Online Dictionary
SEM (abbreviation)scanning electron microscope; scanning electron microscopy
seminar
