Search engine – A search engine is a web site that let their visitors enter a search query and get as results a sorted list of web pages that are relevant with the search query.  The most popular search engines are, in order of their market share are: Google (www.google.com), Yahoo (search.yahoo.com), MSN / LIVE (search.msn.com / www.live.com) and Ask (www.ask.com).

Search engine marketing (SEM) – Search engine marketing (SEM) is the general term that describes all actions done for promoting a website on the Internet and generates visitors and sales for that site; please note that Search engine optimization (SEO) is included in search engine marketing (SEM).

Search engine optimization (SEO) – Search engine optimization (SEO) is the general term that describes all actions done for improving the placement of a certain site in search engines result pages (SERPS).

Search query – A search query is the text (keyword or key phrase) which is entered by a visitor of a search engine in order to obtain the desired search results. It is also called a query.

Search engine results page(s) (SERPS) – Search engine results page(s) (SERPS) shows the rankings of a certain site in search engines.

Search term – A search term is a keyword or key phrase used in a search engine query.

SEM – SEM is an acronym for “search engine marketing” and it is used to describe all actions done for promoting a website on the Internet and generates visitors and sales for that site; please note that Search engine optimization (SEO) is included in search engine marketing (SEM).

SEO – SEO is an acronym for “search engine optimization” and it is used to describe all actions done for improving the placement of a certain site in search engines result pages (SERPS).

SERP(s) – SERP(s) is an acronym for “search engine results page” and it is used to show the rankings of a certain site in search engines.

Spam – (here) Spam is another generic term for all black hat techniques, which are disallowed by search engines. It generally exploits a bug in search engine algorithm and makes a site to rank high in a very short period of time. However most of the times the effect is a short one and in a matter of months, weeks or even days the site is heavy penalized or even completely banned from search engines.

Spamming – (here) Spamming is the act of using any black hat techniques, which are disallowed by search engines.

Spider – A spider is a program that is used by a search engine to automatically explore the web and download, analyze and save the content of any page it finds. It is also called bot, crawler, or robot.

Splash page – A splash page is a home page without any real content, which is used only to welcome the visitor (generally by using a fancy flash intro). They are not recommended from a SEO perspective because the page with most links from the site (the main page) has no real content and though can hardly rank high. Also they are not recommended from a visitor perspective too because it delays the visitors from reaching the content of the site.

Sponsored placement – A sponsored placement in a search engine or directory signifies the fact that the site paid for the listing; most of the times the sponsored listings are less relevant than the organic results. It is also called paid placement.

Standard compliant – A standard compliant page is a page that has a valid W3C code; although there is no clear prove that compliance with the W3C standard is included in search engine algorithms there are quite a lot of SEO experts that believe it is. For more details about W3C compliance or for checking if your site is W3C compliant feel free to visit validator.w3.org.

Stemming – Stemming is a technique used by search engines for determining the most relevant pages for a certain search query, by using not only the exact form of a search term, but also its root form (for example if the search term is “driving” than it will also return pages containing the “driver” keyword).

Stop words – Stop words are those very common words (like “the”, “a” or “an”) that are ignored by search engines when found on a web page or in a search query (for example for search engines “the best gift” and “best gift” phrases are identical).

Supplemental pages – Supplemental pages are those pages that are not considered qualitative enough for making to the main Google index; (ex: pages with duplicated or not enough content, pages with dynamic URLs. Supplemental pages are included in SERPs only if there are not enough pages regarding the specific search query in the main index.