killing three birds with one stone
A humorous or emphatic expression meaning to achieve three benefits from a single action. Less common than 一石二鳥, and often used in casual or creative contexts.
See also: 一石二鳥
With this app, it helps with study, work, and hobbies. It's truly killing three birds with one stone.
一石二鳥 is the common expression for 'killing two birds with one stone'. 一石三鳥 is a less common, playful variant emphasizing an even greater efficiency.
A Japanese coinage modeled on the idiom 一石二鳥 (killing two birds with one stone), replacing 二 (two) with 三 (three) for humorous or emphatic effect. The exact origin is uncertain, but it likely arose as a playful extension in modern Japanese.