This is the 10061st most frequent French word.
gras
Fat; rich; greasy.
The word 'gras' is used here as an adjective describing the dish, implying that it contains too much fat.
Ce plat est trop gras pour être sain.
This dish is too fatty to be healthy.
In this sentence, 'gras' is used as a noun referring to 'bold', indicating the style of writing.
Il a écrit son nom en gras sur le tableau.
He wrote his name in bold on the board.
Here, 'Mardi Gras' is a proper noun referring to the traditional festival celebrated before Lent.