[on the air] {adj.} or {adv. phr.} Broadcasting or being broadcast […]

[on the alert] {adj. phr.} Alert; watchful; careful. * /Campers must […]

[on the average] See: [ON AN AVERAGE].

[on the back] See: [PAT ON THE BACK].

[on the ball] {adj. phr.}, {informal} 1. Paying attention and doing […]

[on the bandwagon] {adj. phr.}, {informal} In or into the newest […]

[on the barrelhead] See: [CASH ON THE BARRELHEAD].

[on the beam] {adv.} or {adj. phr.} 1. (Of an airplane) […]

[on the bench] 1. Sitting in a law court as a […]

[on the blink] {adj. phr.} Faulty; malfunctioning; inoperative. * /I need […]