This is the 1990th most frequent Portuguese word.
amarelo
Yellow.
Here 'amarelo' is used as an adjective describing the characteristic color of the sun.
O sol estava amarelo durante todo o dia.
The sun was yellow all day long.
In this sentence, 'amarelo' is used as a noun, referencing the yellow paint or color.
Eu pintei a casa de amarelo para trazer mais alegria.
I painted the house yellow to bring more joy.
Here 'amarela' is an adjective agreeing in gender with the noun 'flor' it describes.