What does the word thorn mean?

Usage examples for thorn

  1. It was, moreover, a perpetual thorn in the side of the Assyrians. – Early Israel and the Surrounding Nations by Archibald Sayce
  2. It bore the rose as well as the thorn. – Charles Lamb by Barry Cornwall
  3. But help me to be a thorn in their sides- just a little- just a little longer. – Romance by Joseph Conrad and F.M. Hueffer