Knocking on Wood

1919

Knocking on wood

The superstition of rapping on wood after a boast of a piece of luck is of European origin. The raps were supposed to drive away evil spirits vexed by others' good fortune. The raps later signified the Trinity, and the necessity for rapping on wood was because that was the material of the cross. The expression dates from a custom in vogue five thousand years ago.

--Middletown Daily Herald, Middletown, New York, June 2, 1919, page 4.