What does the word understand mean?

Usage examples for understand

  1. And who should understand them if he did not? – The Heart of Unaga by Ridgwell Cullum
  2. I don't understand it at all, not at all. – Atlantida by Pierre Benoit
  3. If I could only make any of them understand anything! – Slippy McGee, Sometimes Known as the Butterfly Man by Marie Conway Oemler