A foot with icicles hanging off it

Kill two birds with one stone

Meaning: Accomplish two tasks at once

Originated in: 🇬🇧 United Kingdom

Earliest attestation: The Questions Concerning Liberty, Necessity, and Chance by Dr. John Bramhall (1656)

To kill two birds with one stone means to accomplish two separate goals with one plan or action. Some theoretical examples would be:

It’s when you do something you need to do and can accomplish a second goal with little extra effort. The objectives coincidentally align. That’s not to say that it couldn’t have been planned—situations rarely work out so well without a little foresight, but it is not noteworthy when the objectives are naturally linked.

The idea is of a man hunting birds with a sling. Usually he would only be able to kill one bird per stone. However, if he were able to line up two birds, he could theoretically kill both with a single stone and save time and ammunition. It is a metaphor for efficiency.