The Collins American Dictionary defines memento mori as ‘any reminder of death’.
Memento mori is a Latin phrase that literally means ‘remember you must die’. In classical studies in school, a long time ago now, I was taught that when a Roman general enjoyed a triumph, that is, the great parade to celebrate a victory, a servant would stand behind him in the chariot, murmuring this phrase to remind the general that he was human like everyone else and would come to the same end as everyone else.
Memento mori also refers to a genre of art that explores issues of mortality and death, which particularly flowered in the late Medieval and Renaissance eras but isn’t exclusive to that time. Pictorial art of this nature features death motifs such as skulls or decay. The art may be intended quite didactically, with the intention of encouraging the viewer to consider serious matters rather than frivolities. Literature gets in on the act with works like Thomas Gray’s 1783 Elegy Written in a Country Churchyard, which contains lines such as ‘the paths of glory lead but to the grave.’ This Wikipedia link gives some more background on the expression.
The first word of this phrase, memento, is of course used on its own without the macabre associations to refer to an item kept as a souvenir or remembrance of an event or a person. The tradition of post-mortem photography in Victorian times effectively combined the meanings of memento and memento mori. Sometimes a picture taken after death could be the only record of an individual, especially if a child had died, and this is commonly referred to as memento mori photography.
In television, the phrase has been used as an episode title and focus with varying degrees of success and relevance. A quick search of the internet reveals an episode list including X-Files, Stargate-SG1, Chicago Hope, and The Road to Avonlea. There’s also a Korean horror movie using the phrase as a title.
Let’s leave the final word with Benton Fraser of Due South:
It was, Fraser reflected, a somewhat ambiguous memento mori to be so continually haunted by your father’s ghost.