An alibi is a form of defense used in criminal procedure wherein the accused attempts to prove that he or she was in some other place at the time the alleged offense was committed. The Criminal Law Deskbook of Criminal Procedure  states: "Alibi is different from all of the other defenses; it is based upon the premise that the defendant is truly innocent." In the Latin language alibī means "somewhere else." Law . the defense by an accused person of having been elsewhere at the time an alleged offense was committed. An excuse, especially to avoid blame. A person used as one's excuse: My sick grandmother was my alibi for missing school.