Besides "L'Ultima Cena", "The Last Supper" is also named "Il Cenacolo" in Italian. Why is it also named this way and when was it it first used?
From Dizionario Etimologico della Lingua Italiana (Cortellazzo-Zoli):
Cenacolo - stanza ove anticamente si cenava, e, in particolare, luogo nel quale Gesù e gli Apostoli consumarono l'ultima cena (referenced in the works of the Dominican friar Domenico Cavalca)
While in Latin cenaculum was used generically as the place where people ate, in Italian it soon took the explicit meaning of the place where the Last Supper happened.
Keep in mind that in modern Italian "cenacolo" is also a meeting of intellectuals.