Posted by Shae on October 12, 2002
It's an expression used when wishing good fortune to a person or venture. "Good luck at the job interview! Touching wood for you!" "I hope the weather is good for the barbeque tomorrow. Touch wood!"
I've been told it refers to a medieval custom of touching a piece of the "True Cross," or of a reliquary that contained such a piece. Can anybody corroborate this?