What is the meaning of gantlet?

noun

• To offer or accept a challenge.
  • usage: "threw down the gauntlet"; "took up the gauntlet"
  • synonyms: gauntlet
• A glove of armored leather; protects the hand.
  • synonyms: gauntlet, metal glove
• A glove with long sleeve.
  • synonyms: gauntlet
• The convergence of two parallel railroad tracks in a narrow place; the inner rails cross and run parallel and then diverge so a train remains on its own tracks at all times.
• A form of punishment in which a person is forced to run between two lines of men facing each other and armed with clubs or whips to beat the victim.
  • synonyms: gauntlet