I was writing an article on the beginnings of the crossword earlier today and looked at the contents of the world's first-ever crossword, published in the New York World in 1913 (you can see it here, where you can click on a link at the bottom of the page to see the answers). Most of the words in it appear regularly in today's crosswords, but there are four that don't: nard, neif, sere and tane.
Nard is an aromatic plant, as the clue says, and is a word that has been in use in English since almost the beginnings of the language. Sere means a talon, but the OED describes this word as obsolete. Neif and tane are dialect words and are not in the OED under that form, although the words do appear on the relevant pages. Neif means a fist, as the crossword correctly says, but the OED has it as a variation of nieve, which it describes as chiefly Scottish, Irish or northern English. Tane is under the 'tone' headword where 'tone' is a pronoun, described as Scottish or northern English. It is usually prefaced by 'the' and the OED says that 'the tane' is still in common use in some dialects today to mean 'the one'. These words must have proved quite difficult for New York solvers to crack when they did the puzzle!
I don't know the terms 'the tane', 't'ane' or 't'one' but I do know 't'other' with which these expressions are often paired. T'other, which can also be spelt tother without the apostrophe, is reasonably common, especially in Yorkshire and the north-east of England. It's in the sixth paragraph of this obituary from today's Northern Echo, which covers North Yorkshire, Darlington, Middlesbrough and Durham. It also appears in the first line of this recent article from an American site. T'other and tother appear in shorter dictionaries. Chambers and the Oxford Dictionary of English label the words 'humorous or dialect' while Collins has 'archaic or dialect'.