Other forms: thinking outside the box; thinks outside the box; thought outside the box
To think outside the box is to consider things in an unconventional or creative way. Those who think outside the box may come up with innovative or unusual ideas.
When someone — such as your boss or your teacher — tells you to think outside the box, they are asking you to question the way things are currently being done and look for a new perspective that challenges the status quo. The idiom is widely believed to have come from a logic puzzle popular in the 1970s and '80s called the "Nine-Dot Problem." People presented with a three-by-three grid of dots were asked to connect all nine dots using only four straight lines, without lifting the pen. The only way to successfully complete the task was to draw lines that extended "outside the box" created by the grid.