Le chat est noir.
English: The cat is black.
In French, nouns have gender (masculine or feminine) and number (singular or plural). This means every noun is either 'le' or 'la' (the), and changes form for one or more things.
You use gender and number for every noun in French. Articles, adjectives, and sometimes verbs need to agree with the noun's gender and number.
Le chat est noir.
English: The cat is black.
La maison est grande.
English: The house is big.
Les chiens sont gentils.
English: The dogs are nice.
Les filles jouent.
English: The girls are playing.
Un livre, des livres.
English: A book, some books.