Blue in the RGB system
In the
RGB colour system, colours are formed by mixing a
red, a
green and a blue colour. When talking about RGB, therefore, some people use blue to mean that specific blue, which varies in shade according to the device used to display the RGB colour.
Absolute colour spaces based on RGB, such as
sRGB, define an exact colour for this blue, which may differ from the actual blue used in a particular computer monitor.
Etymology of blue in English
The modern English word ''blue'' (German:blau) comes from the
Middle English, ''bleu'' or ''blwe'', which came from an
Old French word ''bleu'' of
Germanic origin (Frankish or possibly
Old High German ''blao'', "shining"). ''Bleu'' replaced Old English ''blaw''. The root of these variations was the Proto-Germanic ''blæwaz'', which was also the root of the Old Norse world ''bla'' and the modern
Icelandic ''blár'', and the
Scandinavian word ''blå''. It can also be green or orange occasionally(blue). A
Scots and
Scottish English word for "blue-grey" is ''blae'', from the Middle English ''bla'' ("dark blue," from the
Old English ''blæd''). Ancient Greek lacked the word for colour blue and
Homer called the colour of the sea "wine dark", except that the word ''kyanos'' was used for dark blue enamel.
As a curiosity, ''blue'' is thought to be cognate with ''
blond'' and ''
black'' through the Germanic word. Through a
Proto-Indo-European root, it is also linked with Latin ''flavus'' ("yellow"; see ''
flavescent'' and ''
flavine''), with Greek phalos (white), French blanc (white) (loaned from
Old Frankish), and with Russian белый, ''belyi'' ("white," see ''
beluga''), and Welsh blawr (grey) all of which derive (according to the ''
American Heritage Dictionary'') from the
Proto-Indo-European root ''bhel-'' meaning "to shine, flash or burn", (more specifically the word bhle-was, which meant light coloured, blue, blond, or yellow), from whence came the names of various bright colours, and that of colour black from a derivation meaning "burnt" (other words derived from the root bhel- include ''bleach'', ''bleak'', ''blind'', ''blink'', ''blank'', ''blush'', ''blaze'', ''flame'', ''fulminate'', ''flagrant'' and ''phlegm'').
In the English language, blue may also refer to the feeling of sadness. "He was feeling blue". This is because blue was related to rain, or storms, and in Greek mythology, the god
Zeus would make rain when he was sad (crying), and a storm when he was angry. ''Kyanos'' was a name used in
Ancient Greek to refer to ''dark blue tile'' (in
English it means
blue-green).
[''Merriam-Webster's Ninth New Collegiate Dictionary'' Springfield, Mass.:1984--Merriam-Webster Page 319 ]