The words ewes, use, yews sound the same but have different meanings and spellings. Why do ewes, use, yews sound the same even though they are completely different words?
The answer is simple: ewes, use, yews are homophones of the English language.
Plural form of ewe.
The condition or fact of being used: a chair in regular use.
use up To consume completely: used up all our money.
To put into service or apply for a purpose; employ.
To avail oneself of; practice: use caution.
Plural form of yew.
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").