Dinner: generally refers to what in many Western cultures is the largest and most formal meal of the day, eaten in the evening. Historically, the largest meal was eaten around midday and was called dinner. It gradually migrated away, especially among the elite, later in the 16th to 19th centuries.The word has different meanings across cultures and can mean a meal of any size, eaten at any time of the day. In particular, it is used on special occasions, such as a Christmas dinner, sometimes still used for a midday or early afternoon lunch. In hot climates, the main meal tends to be eaten in the evening after the temperature has dropped.
The word comes from Old French (ca. 1300) disner meaning “to eat”, from the Gallo-Roman root desjunare (“to break the fast”), from Latin dis- (indicating the opposite of an action) + Late Latin ieiunare (“to fast” ), from Latin ieiunus (“fasting, hunger”).  The Romanian word dejun and the French word déjeuner retain
this etymology and to some extent the meaning (while the Spanish word breakfast and the Portuguese word desjejum are related but used exclusively for breakfast). Finally, the term referred to the heavy main meal of the day, even if it was preceded by breakfast (or even breakfast and lunch).