memento

Memento comes from the imperative form of "meminisse," a Latin verb that literally means "to remember." (The term memento mori, meaning "a reminder of mortality," translates as "remember that you must die.") The history of "memento" makes it clear where its spelling came from, but because a memento often helps one remember a particular moment, people occasionally spell the term "momento." That second version is usually considered a misspelling, but it appears often enough in edited prose to have been considered acceptable for entry in Webster's Third New International Dictionary and the Oxford English Dictionary.