About

gray is a color:

• at the middle between white (lightest) and black (darkest) on the ligthness scale (grayscale)
• achromatic (without hue like white and black)
• without temperature

Mixing a color with gray create a tone.

Rgb Representation

In RGB space where:

BLACK = [0,0,0];
BLACK = "#000000"; //hex
WHITE = [255,255,255]
WHITE = "#FFFFFF"; //hex 16 15 16 16

gray is

GRAY = [127.5, 127.5, 127.5]
GRAY = "#888888"; // hex