“Knock on wood” is an expression that is often used by English speakers, but it is a very unique phrase.  This phrase basically means ‘I hope so’ or ‘if all goes well’.  Knock on wood is a spoken phrase (it is generally not written) and it is an expression used to express a desire to avoid ‘tempting fate’ or to keep something bad from happening.  This phrase is said most often after a person makes a boast* or expresses a hope or desire.  When a person says this phrase they usually knock on something that is made of wood, or any hard surface that is near by.

Here are some examples of how this phrase might be used:

“I think I am finally feeling better – knock on wood.”

“I won’t be late for work again tomorrow – knock on wood.”

“Are your parents paying for you guys to go to France again this summer?”  “Knock on wood!”

 The origin of this phrase comes from old English folklore.  Apparently a long time ago people in England went into the isolated woods to talk privately and tell secrets and they “knocked” on the trees (and trees are made of wood) when they were talking to hide their communication from evil spirits who might make trouble.  The people knocked on wood to keep the spirits from hearing them and keep the good things they wanted to happen from being disrupted.  Another version of this folklore states an almost opposite understanding of the action of knocking on wood.  This other version holds that the act of knocking on trees was to wake up the spirits to make them listen so they could work in favor of a specific request or secret.

* boast = to talk with excessive pride and self-satisfaction