Hi-yo, Everyone!

I’ve heard this expression used over and over again in so many instances—pushing the envelope.  "He’s pushing the envelope." . . . "Let’s push the envelope," and so on.

From what I understand, pushing the envelope means taking something to the nth degree, going as far as one can, as it were.

Does anybody know the origin of this phrase?

Regards, Members!

I think this phrase comes from test-pilot slang. The ‘envelope’ is a wrapper. The aircraft has certain limits that the test pilot has to determine - maximum altitude (ceiling), maximum speed, minimum speed (stall speed) and various manœuvrability limits. These combined form the aeroplane’s envelope - an invisible wrapper around its performance. Thus, the test pilot has to push the aeroplane to its envelope in order to do their job - and going to the extreme limits is, therefore, known as pushing the envelope.

- Acting Pilot Officer Garzo, 1st Dirigible Squadron.

That goes rather well with the notion of the mathematical envelope - a curve (or surface) which is tangential to all curves (or surfaces) in a family of curves (or surfaces).

Thank you, Garzo!  

That explanation is totally different from what I had in mind, which was . . .

someone bribing or paying off somebody else by gently pushing or sliding the cash in an envelope across the table to the recipient. Sorta like "Make him an offer he can’t refuse."

Carry on, Acting Pilot Garzo!