Late 16th century (as a military term denoting a strip of land along the outer edge of a ditch, protected by a parapet): from French, from Italian corridore, alteration (by association with corridore 'runner') of corridoio 'running place', from correre 'to run', from Latin currere. The current sense dates from the early 19th century.

• Corridors are nothing to do with doors. They are ‘running places’. The word comes from Italian corridore, from Latin currere ‘to run’. It started out as a military term for a strip of land along the outer edge of a ditch, protected by a parapet. The modern sense of ‘a long passage in a building’ dates from the early 19th century. See also cursor. Corridors of power refers to the senior levels of government or the civil service, where all the important decision-making takes place behind the scenes. It was popularized by the title of C. P. Snow's novel The Corridors of Power (1964), though Snow did not coin the expression.