Al-Qaza’ can be defined as leaving some of the hair and shaving some of it, and this differs from the thinning of the hair, and this definition is taken from the meaning of the hadith narrated by Abdullah bin Omar, where he said: (If a boy shaves, and leaves here a hair, and here and here, then he pointed to us Ubayy May God lead him to his forelock and the sides of his head).
Based on this hadith mentioned, it can be said that shaving in any place on the head is qaza’, as long as the hair remains in another place: If a Muslim shaves the middle of his head and leaves it on both sides, then this is qaza’.
If both sides of the head are shaved and the middle is left, then it is qaza’.
If it is shaved in front of the head and remains behind it, then it is qaza’.
If it is shaved behind the head and remains in front of it, then it is qaza’.
The reason for naming this adjective from the throat is due to qaza’, based on the origin of the meaning of the word qaza’; As it is called the scattered pieces of clouds, and in that it is an analogy to the head, some of which are shaved and others are left by the scattered cloud.