"Think outside the box" comes from a lesson based on an old puzzle used to test creative thinking: the "nine dot puzzle." You are shown a square array of three rows of three dots. You are told to draw four straight lines that pass through each of the nine dots, without ever lifting your pencil off the paper. The trick is that, to do this, it's necessary to draw lines that go well outside the square formed by the nine dots. Here's one solution: https://playingintheworldgame.files.wordpress.com/2014/03/the-nine-dots-puzzle-solution.jpg Notice how the lines go outside the "box" formed by the nine dots. The point is that to solve problems, you need to be creative, and you must beware of assuming constraints that are not really there. Don't get "boxed in." So, "thinking outside the box" means thinking creatively and being willing to consider non-traditional solutions. Charles F. Kettering invented the electric starter motor for automobiles. Before then, engineers were stuck, because using traditional approaches, a electric motor powerful enough to start a car engine would be much too big and expensive to be feasible. Kettering realized that engineers had assumed a constraint that wasn't there. They assumed the motor had to be big enough to put out that much power continuously, without burning out. Kettering realized that you could use a much smaller motor and operate it under what would normally be overload conditions. It would burn out in a few minutes. But it only needed to operate for a few seconds, so that wasn't a real problem. That was a good example of "thinking outside the box." Unfortunately, "thinking outside the box" has become such an overused, hackneyed phrase that it has become sort of a joke. Anyway, "thinking outside the box" means "take a creative and unrestrained approach to solving problems." "Push the envelope" means "try something bold that's outside the range of what is known to be safe."

No, they are different. "Pushing the envelope" is a shortened form of "pushing the outside of the envelope." It was a phrase used by test pilots and it entered general use through Tom Wolfe's book about the space program, "the right stuff." "The envelope" means an outline on an engineering chart that graphs parameters--like airspeed and altitude--against each other. The envelope outlines all the combinations that have been tested and within which the plane behaves properly and can be flown safely. Somewhere outside the envelope are combinations that are dangerous--the plane might stall, or go into a spin, or the wings might come off. "Pushing the outside of the envelope" is test-pilot understatement. It means "I'm going to try something nobody has tried before, something a little outside the bounds, and see what happens. If the plane doesn't crash, we will add that point to the chart and the envelope becomes a little bigger." In common parlance, it means "to try something bold," or "to go a little outside the known safe limits." For example, a child might "push the envelope" by using bad words in front of his parents to see how they react, and just how bad the bad words really are.

Both of these are idioms that are pretty common in English. However, I wouldn't say they were the same, nor have the same origins. "Thinking outside the box" is usually applied to a creative approach that no one else has attempted. It is often used when someone creates a new process or discovers a novel approach to solving a problem. This phrase means something is unconventional, unique, and entirely different. "Pushing the envelope" describes testing limits and boundaries. This phrase originated with aviation and the testing the performance of an aircraft or it's "flight envelope". Unlike "thinking outside the box", this phrase has to do more about finding, meeting, and exceeding the current limitations with conventional methods.

to some extent, both are similar metaphors. the only difference you could say is that "thinking outside the box" is generally for ideas while "pushing the envelope" could mean exceeding boundaries physically. But they are more or less the same idea.

Hi Anna! "Pushing the envelope" would refer to going beyond a limit. e.g. "My best friend likes to push the envelope when we go drinking by forcing me to drink too much." (Lots of people drink too much) "Thinking outside the box" means thinking in very unique way, different from the vast majority of other people.