The words pew, piu sound the same but have different meanings and spellings. Why do pew, piu sound the same even though they are completely different words?
The answer is simple: pew, piu are homophones of the English language.
One of the long, fixed, backed benches that are arranged in rows for the seating of a congregation in church.
An enclosed compartment in a church that provides seating for a number of people, such as a family.
A little more.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from the GNU version of the Collaborative International Dictionary of English 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").