Connectors

Connectors (Boolean operators) are used in keyword searches to link together two or more terms. The most commonly-used connectors are: AND and OR.

AND narrows a search; you get fewer records, because all concepts must be present in the records found--here the area in color. Use AND to combine different concepts in one search.

computer AND history AND mathematics

OR broadens a search; you get more records because OR includes each of the concepts separately, as well as all concepts when found together. OR is often used to link together related concepts or synonyms.

www OR internet OR web