The words knows, noes, nose sound the same but have different meanings and spellings. Why do knows, noes, nose sound the same even though they are completely different words?
The answer is simple: knows, noes, nose are homophones of the English language.
Third-person singular simple present indicative form of know.
All persons, singular and plural, present form of know.
Plural of no1.
The part of the human face or the forward part of the head of other vertebrates that contains the nostrils and organs of smell and forms the beginning of the respiratory tract.
The sense of smell: a dog with a good nose.
The ability to detect, sense, or discover as if by smell: has a nose for gossip.
The characteristic smell of a wine or liqueur; bouquet.
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").