Learn Hardcore Spanish (Latin America): El libro está cerrado.

We use está (from the verb estar) to describe a temporary state or condition of the book (it is closed at the moment). The verb ser (es) would imply a more permanent characteristic, which doesn’t make sense here since the book being closed is not a permanent trait.

Is cerrado an adjective, and why is it in the masculine form?

Yes, cerrado is an adjective meaning closed. In Spanish, adjectives need to agree in gender and number with the noun they modify. Since libro is masculine and singular, we use cerrado in the masculine singular form.

Could I say El libro está cerrada?

No, that would be grammatically incorrect. You must match the adjective’s gender: because libro is masculine, the adjective must also be masculine (cerrado). If the noun were feminine (e.g., la puerta), then you would say la puerta está cerrada.

Does El libro está cerrado only refer to the physical state of the book?