“Aide-mémoire” translates directly from French to “memory aid,” but a good synonym for it could be “mnemonic device.” The latter term is a pattern or association used to remember something, such as the word “HOMES” to remember the names of the Great Lakes (Huron, Ontario, Michigan, Erie, and Superior). But an aide-mémoire isn’t always so pithy — it can be a sticky-note reminder, a guide book, a flier, or anything else that helps retain memories. The other definition of “aide-mémoire” (“an informal diplomatic memo”) came into English around the same time, but it didn’t catch hold as firmly as the memory aid usage did.