Growing up it was always gray like the Crayola crayon. Now, at work especially, it's grey, for the colors of clothing.
From RhymeZone.com:
Definitions of GREY
noun: Englishman who as Prime minister implemented social reforms including the abolition of slavery throughout the British Empire (1764-1845)
noun: Queen of England for nine days in 1553; she was quickly replaced by Mary Tudor and beheaded for treason (1537-1554)
noun: United States writer of western adventure novels (1875-1939)
noun: gray clothing
noun: any organization or party whose uniforms or badges are gray
noun: a neutral achromatic color midway between white and black
verb: turn gray
verb: make gray
adjective: an achromatic color of any lightness between the extremes of black and white
adjective: intermediate in character or position
adjective: used to signify the Confederate forces in the Civil War (who wore gray uniforms)
adjective: showing characteristics of age, especially having gray or white hair
adjective: darkened with overcast
name: A surname (common: 1 in 25000 families; popularity rank in the U.S.: #2782)
Definitions of GRAY
noun: horse of a light grey or whitish color
noun: gray clothing
Example: "He was dressed in gray"
noun: a neutral achromatic color midway between white and black
noun: any organization or party whose uniforms or badges are gray
Example: "The Confederate army was a vast gray"
noun: United States botanist who specialized in North American flora and who was an early supporter of Darwin's theories of evolution (1810-1888)
noun: American navigator who twice circumnavigated the globe and who discovered the Columbia River (1755-1806)
noun: English poet best known for his elegy written in a country church-yard (1716-1771)
verb: turn gray
Example: "Her hair began to gray"
verb: make gray
adjective: clothed in gray or a gray costume
Example: "Gray Ladies are volunteer workers in the American Red Cross"
adjective: an achromatic color of any lightness between the extremes of black and white
Example: "Gray flannel suit"
adjective: intermediate in character or position
Example: "A gray area between clearly legal and strictly illegal"
adjective: used to signify the Confederate forces in the Civil War (who wore gray uniforms)
Example: "A stalwart gray figure"
adjective: showing characteristics of age, especially having gray or white hair
adjective: darkened with overcast
Example: "A gray rainy afternoon"
name: A surname (very common: 1 in 943 families; popularity rank in the U.S.: #69)
For the most part, the are one and the same. Looking further at RhymeZone:
Related words GRAY
Synonyms:
achromatic, cloudy, colorless, dull, gray-haired, gray-headed, grayish, grayness, grey-haired, grey-headed, greyish, greyness, hoar, hoary, intermediate, leaden, old, southern, white-haired
More general:
achromatic color, achromatic colour, apparel, clothes, clothing, color, colour, discolor, discolour, mount, organisation, organization, riding horse, saddle horse, vesture, wear, wearing apparel
More specific:
ash gray, charcoal, charcoal gray, dappled-gray, dappled-grey, dapple-gray, dapple-grey, davy's gray, iron blue, iron-gray, iron-grey, oxford gray, silver, silver gray, steel gray, tattletale gray, tattletale grey
Related words GREY
Synonyms:
achromatic, cloudy, colorless, dull, gray-haired, gray-headed, grayish, grayness, grey-haired, grey-headed, greyish, greyness, hoar, hoary, intermediate, leaden, old, southern, white-haired
More general:
achromatic color, achromatic colour, apparel, clothes, clothing, color, colour, discolor, discolour, organisation, organization, vesture, wear, wearing apparel
More specific:
ash grey, charcoal, charcoal grey, dappled-gray, dappled-grey, dapple-gray, dapple-grey, davy's gray, iron blue, iron-gray, iron-grey, oxford grey, silver, silver grey, tattletale gray, tattletale grey
Scanning across those, they are nearly identical.