Case Sensitive: In general, most search engines will match upper case, lower case, and mixed case as all the same term. Some search engines have the capability to match exact case. Entering a search term in lower case will usually find all cases. In a case sensitive search engine, entering any upper case letter in a search term will invoke the exact case match.

Example:
next finds next, Next, NeXT, neXT
NeXT finds only NeXT