The words peas, pease, pees sound the same but have different meanings and spellings. Why do peas, pease, pees sound the same even though they are completely different words?
The answer is simple: peas, pease, pees are homophones of the English language.
Plural form of pea.
Archaic A pea.
Plural form of pee.
Third-person singular simple present indicative form of pee.
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.