Nouns ending in -as are masculine.
Is repas masculine or feminine?
lerepas
The rule behind it
100% of -as nouns are masculine
In context
Ce restaurant sert deux mille repas par jour.
That restaurant prepares two thousand meals every day.
Je me brosse les dents après les repas.
I brush my teeth clean after meals.
Elle débarrasse toujours la table après un repas.
She always clears the table after a meal.