Correct spelling, explanation: ancient Greeks were the first ones who created an idea of a dining room as a separate place used for eating meals. The word itself, however, comes from the Latin form disiunare, which meant to eat breakfast. The expression dining room entered English from Old French in the times of Middle English.

Definition of dining room:
1. noun – a room used for eating meals;
Let’s serve dinner in the dining room and then we can chill in the living room.

Phrases with dining room:
Some commonly used phrases with dining room are: dining room table, guest dining room, elegant dining room;
It’s time to buy a new dining room table as the old one is simply too small for our big family.
Breakfast is served in our cozy guest dining room on the first floor.
The house features an elegant dining room and a modern kitchen.

Incorrect spelling, explanation: the most common word that belongs to the word family of dining room is the word dinner. The latter one is spelled with a double -n letter and because of that many users of English think that the same happens with the word dining room. As a result, the common mistake is to spell the word as dinning room, which is wrong.