Ford uses different nomenclature than other car companies:
But it is one of the following:
Front air dam Front air deflector Front air scoop Radiator air diverter
Do not make the mistake of removing it, and thinking you can live without it. It was put there for a reason, and that reason is. Low speed driving.
The grille and bumper openings aren't sufficient to allow enough air into the radiator/Ac Condenser, so that catches the air and rives it up into the radiator.
By the way, Nice Stang!