Do you need a flue on a wood burning stove?

The flue is the chimney, where the hot air rises through, thereby drawing more air into the front of the stove.

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The flue is the duct that carries gaseous combustion products away from the fire. It includes the chimney, but also includes the stovepipe and possibly other ducts.

In the case of a wood kitchen range, it includes the duct surrounding the oven, so the gasses go over, down the far side, beneath toward the front, toward the rear, and up the back, surrounding the oven on all sides but the door and the side where the firebox is.

In a masonry heater, the flue is very large and directs the gasses around a series of baffles so the masonry can heat up.