Definition of "anachronism"

Indeed, that Hall of the Upper Temple is a sight not uninteresting, and with the exception of some trifling improvements and anachronisms which have been introduced into the practice there, a man may sit down and fancy that he joins in a meal of the seventeenth century.

1848 November – 1850 December, William Makepeace Thackeray, chapter 30, in The History of Pendennis. […], volumes (please specify |volume=I or II), London: Bradbury and Evans, […], published 1849–1850

[W]e beg the reader to understand that we only commit anachronisms when we choose and when by a daring violation of those natural laws some great ethical truth is to be advanced […]

1848 November – 1850 December, William Makepeace Thackeray, chapter 53, in The History of Pendennis. […], volumes (please specify |volume=I or II), London: Bradbury and Evans, […], published 1849–1850

You are too young—it is an anachronism for you to have such thoughts

1871, George Eliot [pseudonym; Mary Ann Evans], chapter XXII, in Middlemarch […], volume I, Edinburgh, London: William Blackwood and Sons, book II, page 400

His movements, his clothes, everything about him, seemed slightly out of place in this assembly. He spoiled the pattern; like Alvin, he was an anachronism.

1956, Arthur C. Clarke, The City and the Stars, page 32

There exist in Europe a number of independent or semi-independent countries which are complete anachronisms, they are mini-countries which have little business existing in this hurly-burly century, but somehow they survive.

1971, Ken Welsh, Hitch-hiker's Guide to Europe, revised and updated edition, London: Pan, published 1975, page 142

The old portions are perfectly preserved […] and yet right there, in their literal backyard, rise the newer portions, the Star Wars district and the Avatar experience, offering the best of current theme park technologies to match the lovingly maintained anachronisms.

2023 March 3, Ross Douthat, “What a Visit to Disney World Reveals About America”, in The New York Times‎