What does the word how mean?

Usage examples for how

  1. How are you, Mirotaine! – San-Cravate; or, The Messengers; Little Streams by Charles Paul de Kock
  2. But how much shall you be with us? – The Fruit of the Tree by Edith Wharton
  3. Yes, but how did you know it? – The Tin Soldier by Temple Bailey