The words ess, s sound the same but have different meanings and spellings. Why do ess, s sound the same even though they are completely different words?
The answer is simple: ess, s are homophones of the English language.
The letter s.
The 19th letter of the modern English alphabet.
Any of the speech sounds represented by the letter s.
The 19th in a series.
Something shaped like the letter S.
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.