The words rapper, wrapper sound the same but have different meanings and spellings. Why do rapper, wrapper sound the same even though they are completely different words?
The answer is simple: rapper, wrapper are homophones of the English language.
One that raps or strikes, especially a door knocker.
Music One who performs rap.
The material encircling a magazine or newspaper sent by mail.
That in which an object is wrapped or covered, as:
The material, such as paper, in which something is wrapped: a candy wrapper.
A book jacket.
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").