What is considered a standard drink in the united states?

Depends on the drink. Standard drink has 14 gms pure alcohol so: beer (5% alcohol)-12 oz malt liq (7%)-8-9 oz wine (12%)-5 oz hard liquor/spirits (80 proof/40%)-1.5 oz (jigger) mixed drinks can vary- depends how well you know the bartender, so be careful, especially if you plan on driving later.
As follows. One alcoholic drink is a 12 oz beer, an 8-9 oz high gravity beer, a 4-5 oz wine, or a 1.5 oz liquor with a 40% alcohol content.