A search engine is a tool or program which allows general or topic-specific searching for relevant sites or information on the Web ie google, yahoo, bing etc.
Search engine optimization (SEO) is the use of various techniques to improve a web site's ranking in search engines in the hopes of attracting more visitors through unpaid search results.

Other forms of search engine marketing (SEM) target paid listings. In general, the earlier and more frequently a site appears in the search results list, the more visitors it will receive from the search engine. SEO may target different kinds of search, including image search, local search, video search and industry-specific vertical search engines. This gives a web site web presence.

The acronym "SEO" can refer to "search engine optimizers," a term adopted by an industry of consultants like Top Host Kenya who carry out optimization projects on behalf of clients. Because effective SEO may require changes to the HTML source code of a site, SEO tactics may be incorporated into web site development and design. The term "search engine friendly" may be used to describe web site designs, menus, content management systems, images, videos, shopping carts, and other elements that have been optimized for the purpose of search engine exposure.
Top Host Kenya also offers services of search engine optimization.