What is a faskh?

So there are three ways in which a marriage can be invalidated. One is via a talaq, where the husband gives the talaq to his wife. The second is via a khula, which is when the wife requests the end of the marriage and the husband agrees, so the husband has to agree to it. The third one is by a faskh. A faskh means an annulment. So essentially something's happened in the marriage. You go to a judge or a sharia council and they will annul the marriage because of something significant that's happened within it.