The words grays, graze sound the same but have different meanings and spellings. Why do grays, graze sound the same even though they are completely different words?
The answer is simple: grays, graze are homophones of the English language.
Plural form of gray.
Third-person singular simple present indicative form of gray.
To feed on growing grasses and herbage.
Informal To eat a variety of appetizers as a full meal.
Informal To eat snacks throughout the day in place of full meals.
To feed on (herbage) in a field or on pastureland.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License, from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.