Named colors beginning with C come from many places — CSS/W3C named colors, brand and paint palettes, Pantone and RAL naming, traditional Japanese, Indian, and European color vocabularies, and community color-survey names such as the xkcd survey, alongside other widely-circulated public color databases. Where a primary source defines an official value, the entry says so; other hex values are best read as common digital approximations. This page lists a curated, deduplicated selection, including the eight CSS-named C-colors: cadetblue, chartreuse, chocolate, coral, cornflowerblue, cornsilk, crimson, and cyan (the last of which is an alias for aqua). Of those eight, only Cyan (as aqua) belonged to the original sixteen basic HTML colors; the other seven were inherited later from the extended X11/SVG color-name list.

A few claim the title. Cyan is one of the four process-printing primaries (the C in CMYK) and one of the additive RGB secondaries — arguably the most universally important C-color in printing and digital imaging. Crimson is a CSS named color and a deeply embedded color word in English for over five centuries. Cobalt Blue connects two distinct histories: cobalt compounds have colored blue glass and ceramics since antiquity (notably "blue-and-white" porcelain), while the modern artist pigment named cobalt blue dates to the early 19th century. And Cosmic Latte — the average color of the universe, calculated from a survey of 200,000 galaxies — is perhaps the most-quoted scientific color name of the 21st century.

In 2001, Johns Hopkins astronomers Karl Glazebrook and Ivan Baldry set out to calculate the average color of the universe by combining the spectra of more than 200,000 galaxies from the 2dF Galaxy Redshift Survey. Their first announcement put the average at a pale greenish white — a striking result that drew worldwide press. A software calibration error was soon found; the corrected color, published in The Astrophysical Journal in 2002, was a warm pale beige. Glazebrook ran an informal public-naming contest; suggestions included "Skyvory," "Univeige," "Primordial Clam Chowder," and "Big Bang Buff." Astronomer Peter Drum's "Cappuccino Cosmico" got the most votes, but the researchers preferred his other entry, "Cosmic Latte" — partly because latteo is the Italian word for "milky," echoing the Via Lattea (Milky Way) and Galileo's native language. The hex value is #FFF8E7.

Both are 19th-century artist pigments based on cobalt compounds, but their character is distinct. Cobalt Blue (cobalt(II) aluminate, CoAl2O4 — identified by Louis Jacques Thénard in 1802) is a deep, slightly violet-leaning true blue. Cerulean Blue (cobalt stannate, CoSnO3 — commercialized for artist use by George Rowney & Co. in 1860) is a paler, sky-like, slightly green-leaning blue. In practice, oil painters use cobalt blue for deep skies and shadows, and cerulean for the lighter parts of sky and water. Pantone's Cerulean (PMS 15-4020) was the first-ever Pantone Color of the Year, named in late 1999 for the year 2000.

Yes. Carmine is a deep red dye and pigment historically derived from the dried bodies of scale insects: in the Old World, the kermes insect (Kermes vermilio) on Mediterranean oak trees; after the 16th-century Spanish arrival in the Americas, the cochineal insect (Dactylopius coccus) farmed on prickly-pear cactus in Mexico and Peru largely displaced it. Cochineal produced the brilliant scarlet of British Army officers’ coats — rank-and-file soldiers wore cheaper madder red, and the vivid scarlet was extended to all ranks only from the 1870s — as well as the scarlet cassocks of Roman Catholic cardinals and royal regalia across Europe. Carmine is still produced commercially today as a natural colorant for food, cosmetics, and pharmaceuticals — listed on labels as carmine, cochineal extract, Natural Red 4, or E120.

For CSS-named colors (Cadet Blue, Chartreuse, Chocolate, Coral, Cornflower Blue, Cornsilk, Crimson, Cyan), yes — the W3C CSS Color Module specification fixes the exact sRGB values. For Pantone, RAL, and Crayola, hex values are approximate conversions from those brands' proprietary swatch books, which are defined under specific lighting conditions. Different sources occasionally disagree by a few digits; this page uses the most widely-cited public values. For brand and university colors (Carolina Blue, Crimson UA, Cal Poly Green, Castleton Green, Clemson Orange, Columbia Blue), each institution’s own brand guide is the authoritative reference; this page uses the official value where confirmed, and where a swatch is a public catalog approximation the entry says so.