1Of, belonging to, associated with, or characteristic or reminiscent of the first Duke of Wellington.
2Of or relating to Wellington College, Berkshire, a public school founded in 1859 and named after the first Duke of Wellington; especially designating a pupil or former pupil of the school.
1historical A follower or supporter of the first Duke of Wellington, as a military leader or (later) as a Tory statesman and Prime Minister (1828–30 and 1834).
2A pupil of Wellington College. Also (especially in "Old Wellingtonian"): a former pupil of this college.
Early 19th century; earliest use found in The Monthly Review. From the title of Arthur Wellesley, first duke of Wellington + -ian.