Green’s Dictionary of Slang

Dutch n.4

also dutchie
[the precise origins of this term remain debatable. Either the term is an abbr. of SE duchess, strengthened by 17C rum duchess under rum adj. and the rhy. sl. Duchess of Fife n., or, according to the 19C music-hall star Albert Chevalier (1861–1923), whose signature song was entitled ‘My Old Dutch’, the term was semantically linked to another piece of sl., dial n., face. In Chevalier’s version, the original term was ‘my old Dutch clock’, whose face, i.e. dial, resembled that of his wife. See Dutch clock under Dutch adj.1 . Partridge, formerly a partisan of the Duchess, claimed to have changed his mind in the later editions of the DSUE. The OED, however, while citing Chevalier’s song in 1893, has a previous cit., dated four years earlier, and states unequivocally that in this context dutch is ‘an abbr. of duchess’. Given that the first cit. at Dutch clock under Dutch adj.1 is for old Dutch clock and dates from 1845, this would appear to be the root]

[late 19C+] a wife; occas. just a woman; usu. as old Dutch.