This is the 1262nd most frequent French word.
beaux
"Beaux" means "beautiful" or "handsome" in the plural form.
The adjective 'beaux' is used here as the masculine plural form of 'beau' to describe the masculine plural noun 'jardins' (gardens).
Les jardins du château sont très beaux.
The castle's gardens are very beautiful.
'Beaux' is used here to describe 'tableaux' (paintings), which is a masculine plural noun, emphasizing its beauty.
Ces tableaux sont des chefs-d'œuvre très beaux.
These paintings are very beautiful masterpieces.
In this sentence, 'beaux' is an adjective describing 'jours' (days), a masculine plural noun, to highlight their pleasantness.