This is the 768th most frequent French word.
fermé
Closed.
The word 'fermée' is the feminine singular past participle used as an adjective to describe the state of the door being closed.
La porte est fermée.
The door is closed.
Here, 'fermé' is the masculine singular past participle used adjectivally to describe that the shop is not operating today.
Le magasin est fermé aujourd'hui.
The shop is closed today.
In this sentence, 'fermé' is the masculine singular past participle used as part of the passé composé tense to indicate the action of closing the book.