What is the meaning of veteran?

noun

• A serviceman who has seen considerable active service.
  • usage: "the veterans laughed at the new recruits"
  • synonyms: veteran soldier
• A person who has served in the armed forces.
  • synonyms: vet, ex-serviceman
• An experienced person who has been through many battles; someone who has given long service.
  • synonyms: old-timer, oldtimer, old hand, warhorse, old stager, stager

adjective

• Rendered competent through trial and experience.
  • usage: "a seasoned traveler"; "veteran steadiness"; "a veteran officer"
  • synonyms: seasoned