What does the word threshold mean?

Usage examples for threshold

  1. Mercy had listened, waiting on the threshold of her door; Horace had spoken, standing against the opposite wall of the corridor. – The New Magdalen by Wilkie Collins
  2. The door opened and Sheila stood on the threshold. – Outside Inn by Ethel M. Kelley
  3. He paused on the threshold and looked back gravely. – The Sowers by Henry Seton Merriman