veteran a person who has had long experience in a particular field, especially military service. Recorded from the early 16th century, the word comes ultimately from Latin vetus ‘old’.
veteran car in the UK, an old style or model of car, specifically one made before 1916, or (strictly) before 1905.
Veterans Day in the US, a public holiday held on the anniversary of the end of the First World War (11 November) to honour US veterans and victims of all wars. It replaced Armistice Day in 1954.

vet·er·an / ˈvetərən; ˈvetrən/ • n. a person who has had long experience in a particular field: ∎  a person who has served in the military: a veteran of two world wars.

veteran experienced soldier XVI; adj. XVII. — F. vétéran or L. veterānus, f. vetus, veter- old; see -AN.