indigo-bluen.adj.
A. n.
1. The blue-violet colour of indigo.
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the world > matter > colour > named colours > blue or blueness > [noun] > indigo blue
indec1320
indy blue1509
indigo1622
Indian blue1664
indigo-blue1712
1712 E. Cooke Voy. S. Sea 329 The Back of an Indigo Blew.
1794 R. Kirwan Elements Mineral. (ed. 2) I. 27 [Colours] Indigo blue—the deepest, nearly black.
1860 J. Tyndall Glaciers of Alps i. xxvii. 196 They appeared of a decided indigo-blue.
1879 O. N. Rood Mod. Chromatics viii. 93 The original white colour passed rapidly through a greenish blue into a beautiful indigo-blue.
2. The blue colouring matter of indigo, also called indigotin, C16H10N2O2, crystallizing in fine right rhombic prisms of blue colour and metallic lustre; pure indigo.
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the world > matter > colour > named colours > blue or blueness > blue colouring matter > [noun]
indigo-blue1838
indigotin1838
anthocyanin1853
phycocyan1866
stentorin1873
oocyan1875
phycocyanin1875
phycocyanogen1881
the world > life > biology > substance > pigment > [noun] > unspecified pigments > blue
cerulein1806
indigo-blue1838
indigotin1838
1838 T. Thomson Chem. Org. Bodies 198 The sublimed sulphite becomes blue when dissolved in water, probably in consequence of a little indigo blue having been carried over.
1865–72 H. Watts Dict. Chem. III. 250 Schunck has further shown that woad contains indican..which..when boiled with acids splits up into indigo-blue and indiglucin, without the intervention of oxygen.
1875 R. Hunt & F. W. Rudler Ure's Dict. Arts (ed. 7) II. 907 The value of indigo depends entirely on the quantity of indigo-blue which it contains.
B. adj.
Of the blue colour of indigo.
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the world > matter > colour > named colours > blue or blueness > [adjective] > indigo blue
Delft blue1815
indigo-blue1832
indigo1856
1832 W. Macgillivray Trav. & Researches A. von Humboldt xxii. 309 The surface of the bay was of an indigo-blue or violet tint.
1846 G. E. Day tr. J. F. Simon Animal Chem. II. 178 Urine containing an excess of this colouring matter..deposits a brownish, blackish, or frequently an indigo-blue sediment.
This entry has not yet been fully updated (first published 1900; most recently modified version published online June 2022).
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n.adj.1712