It's Italian, and apparently it's known as either Il Cenacolo or L'Ultima Cena, meaning either "the upper room" or "the last supper/dinner".
The weird thing about the word dinner is that, etymologically, it means 'breakfast'. It ultimately comes from the Latin dis + ieiuno, which literally means 'break the fast'. By the time it was borrowed into English from French, it had come to refer to lunch, which was the main meal of the day, and that's why we still have that split. People who ate their largest meal at midday might call it dinner, but people who began to eat the largest meal in the evening called that dinner instead.
Fun fact: in French, the name of every meal means 'breakfast', etymologically speaking. After diner came to mean the midday meal, déjeuner was formed from the same root to mean 'breakfast'. But then dinner came to be the evening meal, déjeuner became the midday meal, and the morning meal became known as petit déjeuner.
