air gap

noun

1

: an air-filled gap in a magnetic or electric circuit (as the space between the field-magnet poles and the armature in a dynamo or motor)

2

: wind gap

3

: the vertical distance between the point where water enters a plumbing fixture (as a tub) and the level at which it would overflow

Word History

First Known Use

1878, in the meaning defined at sense 1

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