The words fays, phase, faze sound the same but have different meanings and spellings. Why do fays, phase, faze sound the same even though they are completely different words?
The answer is simple: fays, phase, faze are homophones of the English language.
Plural form of fay.
To disrupt the composure of; disconcert. See Synonyms at embarrass.
A distinct stage of development: "The American occupation of Japan fell into three successive phases” ( Edwin O. Reischauer).
A temporary manner, attitude, or pattern of behavior: just a passing phase.
An aspect; a part: every phase of the operation.
Astronomy One of the cyclically recurring apparent forms of the moon or a planet.
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.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").