وَهُوَ طَلَبُ حُصُولِ صُورَةِ الشَّيْءِ فِي الذِّهْنِ
It is the request that the representation of a thing be obtained in the mind.
“A representation of a thing” means a mental grasp of an object, meaning, or predicative relationship—not necessarily a visual image. The question seeks to make an unsettled matter intelligible to the mind.
“Which person?” seeks identification of one component. “Did it happen?” seeks a decision about the whole relation. The definition covers both, and their distinction governs the choice and position of questioning words.