re pushing the envelope in apr princeton edu lije cognito princeton edu elijah millgram writes a friend of mine and i were wondering where the expression pushing the envelope comes from anyone out there know everbody has been defining envelope why was the world envelope chosen rather than say shell or boundary in analogy with the envelopes of airships perhaps actually shell might be good push the shell too hard and it the aircraft breaks thomas clarke institute for simulation and training university of central fl research parkway suite orlando fl fax clarke acme ucf edu
