Compound nouns: the last word decides
Mittagessen das
Always In 98.9% of 6,721 common compound nouns, the article comes from the last word.
The last part decides the article: das Essen, so das Mittagessen.
das Mittagessen
It's das Mittagessen. Mittagessen is neuter, plural die Mittagessen.
Das Mittagessen ist um eins.
Lunch is at one.
Mittagessen das
Always In 98.9% of 6,721 common compound nouns, the article comes from the last word.
The last part decides the article: das Essen, so das Mittagessen.