This is the 9972nd most frequent Catalan word.
negro
"Negro" in Catalan means "black" in English.
In this sentence, 'negre' is used as an adjective to describe the color of the dress, meaning black.
Aquest vestit és de color negre.
This dress is black in color.
Here, 'negra' (feminine form of 'negre') describes a characteristic of the book's cover, indicating its color.
Vaig comprar un llibre amb la tapa negra.
I bought a book with a black cover.
In this example, 'negre' serves as an adjective describing the inherent color of the coal.