Dinner is usually the name of the main meal of the day. Depending upon culture, dinner may be the second, third or fourth meal of the day. Originally, though, it referred to the first meal of the day, eaten around noon, and is still occasionally used for a noontime meal, if it is a large or main meal.
Etymology
Originally, dinner referred to the first meal of a two-meal day, a heavy meal occurring about noon, which broke the night's fast in the new day. The word is from the Old French (ca 1300) disner, meaning "breakfast", from the stem of Gallo-Romance desjunare ("to break one's fast"), from Latin dis- ("undo") + Late Latin ieiunare ("to fast"), from Latin ieiunus ("fasting, hungry").[3][4] Eventually, the term shifted to referring to the heavy main meal of the day, even if it had been preceded by a breakfast meal. The (lighter) meal following dinner has traditionally been referred to as supper or tea.
So dinner means breakfast. What a complete fool you are.

Is that pinkie? Are you a school pinkie?
Breakfast is the first meal. Why? Because we break-fast.
Luncheon is next and afternoon tea then dinner and supper.
Unless you are from UWC with 65 languages, then the colloquial is "chop, chop, jildi, jildi", supported by outstretched tongue and clutching the stomach.