grays / graze are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
grays: (noun) a neutral achromatic color midway between white and black. (noun) 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. (noun) English radiobiologist in whose honor the gray (the SI unit of energy for the absorbed dose of radiation) was named (1905-1965). (noun) English poet best known for his elegy written in a country churchyard (1716-1771). (noun) American navigator who twice circumnavigated the globe and who discovered the Columbia River (1755-1806). (noun) United States botanist who specialized in North American flora and who was an early supporter of Darwin's theories of evolution (1810-1888).
graze: (noun) a superficial abrasion. (noun) the act of grazing. (verb) break the skin (of a body part) by scraping. (verb) scrape gently.
grays: g·r·EY·z
graze: g·r·EY·z
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)