Veteran (noun)

1. A person who has had long service or experience in an occupation or activity.
2. A person who has served in the military.

Origin:

Late 16th century: from latin veteranus, from vetus "old", from vetus "old".

Examples:

1. He's a veteran of the Korean War.
2. The company has many veteran employees who have been with it for over 20 years.
3. She's a veteran of the music industry and has been performing for over 25 years.
4. The veterans group was established to help soldiers transition to civilian life.
5. He's a veteran of the political scene and has been involved in many campaigns.