What is meant by al-qur' in the saying of Allah the Exalted: (And those who are divorced must wait three quru')?

Question:
He says: Honorable Shaykh, may Allah grant you success. Regarding the saying of the Exalted and Majestic, , what is meant by the quru' in this verse?

Answer:
This verse is intended to clarify the 'iddah (waiting period) of the divorced woman. The 'iddah of the divorced woman—why does she wait? That is, why does she observe a waiting period after divorce? She does not marry immediately if she is divorced; rather, she waits and observes a period of waiting. This waiting period is called the 'iddah. The 'iddah of the divorced woman who menstruates is three menstrual cycles, and these are the quru'. The quru' are the menstrual periods. As for the one who does not menstruate due to old age or because she has not reached the age of menstruation, she waits for three months. She observes a waiting period of three months in place of the menstrual cycles. This is the view held by the majority of scholars. The first view, or the second view, is that the quru' are the periods of purity between the two menstrual cycles, between the periods. There is no contradiction between the two views, whether they are periods of purity or menstrual periods, because the important point is that three periods of purity necessitate three menstrual cycles, and three menstrual cycles necessitate three periods of purity. This is a difference of variety, not a difference of conflict. And praise be to Allah. Yes.