sRGB
The standard colour space of the web and most screens, defined in the 1990s.
Also: standard RGB
sRGB was created in 1996 by Hewlett-Packard and Microsoft to give computers, monitors and printers a common idea of what RGB numbers mean. It fixes the exact red, green and blue primaries, the white point and the tone curve, all based on typical monitors of the time. It became the default for the web: an image or hex code with no other label is assumed to be sRGB. Its gamut is modest. It cannot show the most vivid greens, cyans and oranges that newer screens are capable of.