To push the envelope is to go past the usual limits of what is done. Push the envelope, pushing the envelope again, push the envelope further.
The envelope is an aviation term for the range of speeds and heights an aircraft can safely fly, and test pilots pushed it outwards. It has nothing to do with stationery, which is what everybody assumes.
1phrasepush the envelopeTo go past the usual limits of what is done.
“The designers like to push the envelope with bold, strange shapes.”
push the envelope is an exceeding.
From aviation, where the flight envelope is the range of conditions an aircraft can safely handle.
Built from
From push (“to continually exert oneself in order to achieve a goal”) + the + envelope (“set of limitations within which a technological system can perform safely and effectively”) (compare flight envelope), referring to the boundary line on a graph of an aircraft’s capabilities, especially those of altitude and speed. The term was popularized by the book The Right Stuff (1979) by the American author and journalist Tom Wolfe (1930–2018) about the pilots engaged in United States postwar research with experimental rocket-powered, high-speed aircraft, and the first Project Mercury astronauts selected for the National Aeronautics and Space Administration’s human spaceflight program.
Etymology from Wiktionary, CC BY-SA
Practised in Idioms