Often used attributively before nouns (mirror image, mirror site).
Translations
The company maintains a mirror site to ensure continuous availability.
L'entreprise maintient un site miroir afin d'assurer une disponibilité continue.
miroirS'emploie surtout dans des groupes nominaux. He wore mirror sunglasses that hid his eyes.
Il portait des lunettes miroir qui cachaient ses yeux.
Definitions
Having the properties of a mirror; reflective or reversed in orientation. He wore mirror sunglasses that hid his eyes.
Duplicated or identical, especially of data, websites, or arrangements; corresponding exactly. The company maintains a mirror site to ensure continuous availability.