Search engine marketing (SEM) is the overall process of combining the two processes of search engine optimisation (SEO) and pay-per-click advertising (PPC).
SEO has strengths where PPC does not, and vice versa. Combining the strengths of each is why the two processes are so powerful when used together.
SEM stands for search engine marketing It is the process of gaining traffic from or visibility on search engines. The phrase is also sometimes shortened to search marketing.