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. This is usually considered a misspelling, but it appears often enough in edited prose to have been entered in most dictionaries as an acceptable variant spelling.