gray vs colour

gray and colour both are nouns.

Word	Noun	Adjective	Verb	Adverb
gray	Yes	Yes	Yes	No
colour	Yes	Yes	Yes	No

As verbs, colour is a hypernym of gray; that is, colour is a word with a broader meaning than gray:

Other hypernyms of gray include color, discolor, discolour.

As verbs, colour is a hypernym of gray; that is, colour is a word with a broader meaning than gray:

Other hypernyms of gray include color, color in, colorise, colorize, colour in, colourise, colourize.

gray (noun)	colour (noun)
horse of a light gray or whitish color	a visual attribute of things that results from the light they emit or transmit or reflect
clothing that is a grey color	the appearance of objects (or light sources) described in terms of a person's perception of their hue and lightness (or brightness) and saturation
a neutral achromatic color midway between white and black	the timbre of a musical sound
any organization or party whose uniforms or badges are grey	interest and variety and intensity
the SI unit of energy absorbed from ionizing radiation; equal to the absorption of one joule of radiation energy by one kilogram of matter; one gray equals 100 rad	an outward or token appearance or form that is deliberately misleading
	(physics) the characteristic of quarks that determines their role in the strong interaction
	any material used for its color

gray (adjective)	colour (adjective)
of an achromatic color of any lightness intermediate between the extremes of white and black	having or capable of producing colors
intermediate in character or position
showing characteristics of age, especially having grey or white hair
used to signify the Confederate forces in the American Civil War (who wore grey uniforms)

gray (verb)	colour (verb)
turn grey	change color, often in an undesired manner
make grey	add color to
	affect as in thought or feeling
	give a deceptive explanation or excuse for
	decorate with colors
	modify or bias