Origin of Knock on Wood

Knocking on wood is a superstition believed to prevent a statement from becoming true. For example, if a person said "I've never had a speeding ticket," they might then knock on something wooden, or say the phrase "knock on wood" to ease their feeling of tempting fate. The origin of knocking on wood for this purpose is believed by some to be from early pagan mythology. Wood gods, or dryads, lived in trees, and people would go to them for blessings and to prevent bad luck. Some historians believe that it comes from an early 19th century children's game, "tiggy touch wood" which is similar to the modern game of tag. It would be impossible to nail down an exact origin however, as this practice exists in some form throughout the world, in every culture.