The words pa, pah, pas sound the same but have different meanings and spellings. Why do pa, pah, pas sound the same even though they are completely different words?
The answer is simple: pa, pah, pas are homophones of the English language.
Informal Father; papa.
Used to express disgust or irritation.
A step or dance.
The right to go before; precedence.
Definitions 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").