What does the word plug mean?

Usage examples for plug

  1. " I think I can read in the faces I see here tonight a great deal of that same spirit, and if the team has it and you fellows behind the team have it, why, I wouldn't give a last year's plug- hat for Claflin's chances next Saturday! – Left Guard Gilbert by Ralph Henry Barbour
  2. After this comes what is called the " plug- and- feather" process. – Diggers in the Earth by Eva March Tappan
  3. He made Masin buy half- a- dozen coarse sponges and tied one upon the upper end of each projecting plug. – The Heart of Rome by Francis Marion Crawford