When I hear people talk about “pushing the envelope,” the mental image I have is of someone pushing paper envelopes around on a desk, but that doesn’t really seem to be what they mean. What is the envelope, and why are so many people pushing it these days?
First of all, you are right to think that, despite the similar sounding phrase, pushing an envelope is not at all like “pushing paper,” as we may do at a desk job. The expression comes from mathematics, but was popularized by test pilots, especially those depicted in Tom Wolfe’s novel, The Right Stuff.
In mathematics and engineering, an envelope is a boundary. In aircraft design and testing, the envelope is the whole set of limitations governing safe operation of the aircraft. The pilots testing new aircraft wanted to take them right to the limits of performance and, if possible, beyond. They did this partly to test the calculated limits and partly to see what would happen.
The expression pushing the envelope has become a well-known metaphor and generally means testing limits and trying out new, often radical ideas. In some business circles, it has become an annoying cliché, and you should probably avoid it—unless you’re a test pilot, of course.