Definition of "ATL"

Abbreviation of Atlantic.  examples

(colloquial, sports) Abbreviation of Atlanta.  examples

Abbreviation of Adriatic Teqball League.  examples

Initialism of authority to leave. Used on a package to advise the deliverer (courier) that the addressee has authorised that the package can be left at the delivery address without being given directly to the addressee or the delivery being signed for.  examples

Initialism of above the line.  examples