Case sensitive
Text or inputted text that is capitalization sensitive. In other words, "Computer" and "computer" are two different words because the "C" is in uppercase and lowercase. Many times a password and/or username may be case sensitive. If this is the case, your username and/or password must have the proper case or you will be unable to log in. Often users will experience the inability to log into a case sensitive login because their caps lock key is on causing the case sensitive password and/or username to fail.
Also see: Case, Keyboard definitions, Lowercase, Uppercase
