memento mori memento \me*men"to\ (?), n.; pl. mementos (#). [l., remember, be mindful, imper. of meminisse to remember. see mention.] a hint, suggestion, token, or memorial, to awaken memory; that which reminds or recalls to memory; a souvenir. seasonable mementos may be useful.
Memento mori (Latin: "remember that you must die") is the medieval Latin theory and practice of reflection on mortality, especially as a means of considering the vanity of earthly life and the transient nature of all earthly goods and pursuits. It is related to the ars moriendi ("The Art of Dying") and related literature. Memento mori has been an important part of ascetic disciplines as a means of perfecting the character, by cultivating detachment and other virtues, and turning the attention towards the immortality of the soul and the afterlife.