To complete, achieve, or take care of two tasks at the same time or with a singular series of actions; to solve two problems with one action or solution. (A variant of the more common "kill two birds with one stone.") I might as well hit two birds with one stone and drop off my tax return while I'm at the mall for the computer part I need. Bike-to-work plans are a great way of hitting two birds with one stone: getting more exercise while cutting down on the cost of your daily commute.