Definition of @ in English:

1At (used to indicate cost or rate per unit)

1. 1.1informal At (in any sense)
   ‘he dealt fairly well with tough issues thrown @ him’
   ‘If you are staying @ a hotel, it will have a laundry service’

2Used in Internet addresses between the user's name and the domain name.

1. 2.1(in an online discussion, especially on the social media application Twitter) preceding the name of a person to whom a comment is directed.
   ‘@Oliver: I'm aware of that fact’