An accepted (but deprecated and rarely used) SI unit of area equal to 100 square metres, or a former unit of approximately the same extent. Symbol: a.
Initialism of advance reader’s edition.
second-person singular simple present of be
The word "are" comes from the Old English earun, which was strengthened by Old Norse forms that replaced other older verbs for "to be." It ultimately traces back to the Proto-Indo-European root meaning "is.