1. To take into custody; to arrest: The police officer apprehended the robber just as he was leaving the scene of the crime.
2. To grasp mentally; to understand: Alice was a candidate who apprehends the significance of political issues.
3. To become conscious of, as through the emotions or senses; to perceive or to understand something: It was easy for TV viewers to apprehend the sorrow and sadness that was expressed by the parents of so many children who died when the boat they were in turned over and sank in the water.

An act by which something is understood or perceived: The teacher, Mrs. Gregson, was hoping for the apprehendings of her students while she was presenting and explaining the topic of chemistry for her class.