Technical spec, includes cross-reference of several standards Down in the body text, you'll find HTML 4 colors, X11 rgb.txt, and HSL, all with good pointers to more information. Turns out the X11 color chart was copied from an MSDN article, which explains why it's sorted alphabetically rather than in any meaningful order. To add insult to injury, the original MSDN article used to have several versions of the table ... but the useful one is now of course a 404. (I don't understand why I'd even be so optimistic as to click on a link in an MSDN article.)

Annotated chart of X11 colors, sortable by column Some of the comments near the top of the chart are good :-)

Chart of colors with their names in several languages Their choice of languages is a little tendentious, though ... The prevalent languages are Finnish, English, German, French, and apparently some Slavic language (I'm guessing Czech, or possibly Slovak)