Q: What is the definition of SEO and SEM?
A: SEO is an acronym for search engine optimization. The purpose of SEO is to positively influence the factors that play into where a search engine decides to rank a website within it's organic results. The organic results being the non-sponsored listings that are typically located on the left hand side of a search results page.
SEM is an acronym for search engine marketing. SEM acts as an umbrella term for all the methods of marketing through search engines. It includes search engine optimization, sponsored listings and any other method by which you can drive traffic to your website through a search engine.