Boolean search: A search for certain data in documents using the words AND, NOT and OR.

Concept search: A search in which search engines locate documents similar in concept to a given keyword.

Full-text index: An index which includes every word, including stop words, of every document that is cataloged.

Fuzzy search: A type of search that locates exact matches in addition to allowing for misspelled matches.

Index: A similar to search engine, index is also commonly referred to as “catalog”. It is a catalog of documents that is searchable, and created by search engine software.

Keyword search: A search that is based off of one, or several, user specified words.

Phrase search: A search whose results contain the exact user specified sentence or phrase.

Precision: The percentage of documents that contain the search words of a given query. The degree of precision depends on the amount of matching documents that are listed. Precision can be illustrated if you consider a search engine that lists 60 documents that match the user query, however there are only 15 that contain the search words. As a result the precision would be 25%.

Proximity search: A search in which users define which words in returned documents, should be nearest to one another.

Query-By-Example: A search in which engines are instructed by the user to locate documents that are similar to a given document. This is also referred to as “find similar.”

Recall: The percentage in which a search engine finds the matching results of the original user query. This can be demonstrated by a search engine that finds only 50 matching documents out of 100. The resulting list would then have a recall of 50% and would list the 50 found.

Relevancy: A determination of how well a result matches the original user query.

Search Engine: A search engine is a program that searches a database or index and retrieves information. Search engine is similar to spider and index.

Spider: A program that follows links on the Internet, scans content and adds them to an index. Spider is often referred to as a search engine.

Stemming: A search engine's ability to find the root form of words. For example, when a user searches for "joining", a search engine is stemming when it also produces results for the word "join".

Stop words: Words that are commonly used such as AND, TO and A, that have little meaning and are commonly ignored by search engines.

Thesaurus: Equivalent words that can be used by search engines to find words that do not appear in resulting documents.

Truncation: A search that allows plurals or different word endings by using a truncation symbol.

Field: A search that retrieves information from a web page and sorts it into fields. The major fields accessed are: URL, domain, text, links, images, etc.

Filter words: Common words in web pages, such as THE, IS, AN, OF, FOR, and DO, that are removed by search engines before the page is added to their database. Filter words are commonly confused with stop words.

Clustering: Search engine that gathers and then groups similar results to a common theme or keyword into clusters.

MetaSearch Engine: A search engine that searches and combines the results of multiple search engines.

Three Types of Search Engines: Descriptions of the three types of search engines that generally fall under the generic label of search engines. This site includes links to each example that is given and easy to understand descriptions.

UMUC: Search the Web & Evaluate Web Resources: An overview of search tools, basic searching, search engine features, and evaluating web resources.

University of Utah: Best Practices for the Web: A discussion on how to understand web searches and how to best optimize web pages for search engines.

Wildcard and Truncation Symbols: An explanation of two methods to use with search terms that have unusual characters or spelling.