To arrange in a line or so as to be parallel: align the tops of a row of pictures; aligned the car with the curb. To adjust (parts of a mechanism, for example) to produce a proper relationship or orientation: aligning the wheels of a truck. To ally (oneself, for example) with one side of an argument or cause: aligned themselves with the free traders. To adhere to a prescribed course of action. To move or be adjusted into proper relationship or orientation.