The words does, dos, doughs, doze sound the same but have different meanings and spellings. Why do does, dos, doughs, doze sound the same even though they are completely different words?
The answer is simple: does, dos, doughs, doze are homophones of the English language.
Third person singular present tense of do1.
Computer Science An operating system that resides on a disk.
Plural form of dough.
To sleep lightly and intermittently.
To spend (time) dozing or as if dozing: dozed the summer away.
A short, light sleep.
doze off To fall into a light sleep.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from Wiktionary, Creative Commons Attribution/Share-Alike License 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").