Etymology
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indigo (n.)
17c. spelling change of indico (1550s), "blue powder obtained from certain plants and used as a dye," from Spanish indico, Portuguese endego, and Dutch (via Portuguese) indigo, all from Latin indicum "indigo," from Greek indikon "blue dye from India," literally "Indian (substance)," neuter of indikos "Indian," from India (see India).

Replaced Middle English ynde (late 13c., from Old French inde "indigo; blue, violet" (13c.), from Latin indicum). Earlier name in Mediterranean languages was annil, anil (see aniline). As "the color of indigo" from 1620s. As the name of the violet-blue color of the spectrum, 1704 (Newton).
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cyanine (n.)

"blue coloring matter of certain flowers," 1855; see cyan- + -ine (2).

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perse (adj.)

late 13c., "blue, bluish-gray," later "rich, dark blue; purplish-black," from Old French pers "(dark) blue, livid; wan, pale," from Late Latin persus, perhaps a back-formation from one of the early European forms of Persia. Compare indigo, from India.

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bice (n.)
"pale blue color," early 15c., shortened from blew bis "blue bice," from French bis "swarthy, brownish-gray" (12c.), a word of unknown origin, cognate with Italian bigio. Via French combinations azur bis, vert bis, names given to two dark colors used in painting, the word came into English with a sense of "blue" or "green."
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prokaryotic (adj.)

"having no nuclear membrane in its cell" (as bacteria and blue-green algae), 1957, from prokaryote + -ic. Related: Prokaryon.

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Prussian 

1550s (n.), "native or inhabitant of Prussia;" 1560s (adj.), "of or pertaining to Prussia;" from Prussia + -an. In reference to the language of the earlier inhabitants of (East) Prussia, which was closely related to Lithuanian, by 1888. It was spoken between the lower Vistula and the Niemen and was extinct by the end of 17c.  Prussian blue pigment (1724) came to English from French bleu de Prusse, so called for being discovered in Berlin, the Prussian capital.

All in all, it seems that Prussian blue was synthesised for the first time around 1706 by the Swiss immigrant Johann Jacob Diesbach in Berlin. [Jens Bartoll and Bärbel Jackisch, "Prussian Blue: A Chronology of the Early Years," in Zeitschrift für Kunsttechnologie und Konservierung 24, No. 1, 2010]

Early German sources refer to it as Preußisches Ultra-Marin and berliner blau. Prussic acid (1790), is from French acide prussique, so called in reference to Prussian blue pigment, to which it is chemically related.

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tanzanite (n.)
violet-blue gemstone, 1968, named by Henry B. Platt, vice president of Tiffany & Co., because the stone was discovered in the African nation of Tanzania.
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hyacinth (n.)
1550s, "the plant hyacinth;" re-Greeked from jacinth (late 14c.) "hyacinth; blue cornflower," which earlier was the name of a precious stone blue (rarely red) in color (c. 1200), from Old French jacinte and Medieval Latin jacintus, ultimately from Greek hyakinthos, which is probably ultimately from a non-Indo-European Mediterranean language.

Used in ancient Greece of a blue gem, perhaps sapphire, and of a purple or deep red flower, but exactly which one is unknown (gladiolus, iris, and larkspur have been suggested). It is fabled to have sprung from the blood of Hyakinthos, Laconian youth beloved by Apollo and accidentally slain by him. The flower is said to have the letters "AI" or "AIAI" (Greek cry of grief) on its petals. The modern use in reference to a particular flowering plant genus is from 1570s. Related: Hyacinthine.
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glass (n.)
Old English glæs "glass; a glass vessel," from Proto-Germanic *glasam "glass" (source also of Old Saxon glas, Middle Dutch and Dutch glas, German Glas, Old Norse gler "glass, looking glass," Danish glar), from PIE root *ghel- (2) "to shine," with derivatives denoting bright colors or materials. The PIE root also is the ancestor of widespread words for gray, blue, green, and yellow, such as Old English glær "amber," Latin glaesum "amber" (which might be from Germanic), Old Irish glass "green, blue, gray," Welsh glas "blue."

Restricted sense of "drinking glass" is from early 13c. and now excludes other glass vessels. Meaning "a glass mirror" is from 14c. Meaning "glass filled with running sand to measure time" is from 1550s; meaning "observing instrument" is from 1610s.
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sloe (n.)

fruit of the blackthorn, Old English slah (plural slan), from Proto-Germanic *slaikhwon (source also of Middle Dutch sleeu, Dutch slee, Old High German sleha, German Schlehe), from PIE *sleiə- "blue, bluish, blue-black" (see livid).

The vowel has been influenced by that in the old plural form, which according to OED persisted into the 17c. Scottish slae preserves the older vowel. Sloe-eyed is attested from 1804; sloe gin first recorded 1878.

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