What is the meaning of spur?

noun

• A verbalization that encourages you to attempt something.
  • usage: "the ceaseless prodding got on his nerves"
  • synonyms: goad, goading, prod, prodding, urging, spurring
• Any sharply pointed projection.
  • synonyms: spine, acantha
• Tubular extension at the base of the corolla in some flowers.
• A sharp prod fixed to a rider's heel and used to urge a horse onward.
  • usage: "cowboys know not to squat with their spurs on"
  • synonyms: gad
• A railway line connected to a trunk line.
  • synonyms: branch line, spur track

verb

• Incite or stimulate.
  • usage: "The Academy was formed to spur research"
• Give heart or courage to.
  • synonyms: goad
• Strike with a spur.
• Goad with spurs.
  • usage: "the rider spurred his horse"
• Equip with spurs.
  • usage: "spur horses"