Hex code
A six-character code, such as #FF9933, that gives a colour's red, green and blue values for the web.
Also: hex colour, hexadecimal colour
A hex code is a compact way of writing an RGB colour. After the hash sign come three pairs of characters, for red, green and blue. Each pair is a number from 0 to 255 written in base sixteen, which uses the digits 0 to 9 and the letters A to F. So 00 is none and FF is full. #000000 is black, #FFFFFF is white and #FF0000 is pure red. Two extra characters can be added for transparency. Hex codes are the usual way to specify colours in web pages and design tools.