The words cross, crosse sound the same but have different meanings and spellings. Why do cross, crosse sound the same even though they are completely different words?
The answer is simple: cross, crosse are homophones of the English language.
An upright post with a transverse piece near the top, on which condemned persons were executed in ancient times.
The upright post with a transverse piece upon which Jesus was crucified.
A crucifix.
Any of various modifications of the cross design, such as a Latin cross or Maltese cross.
Sports The stick used in lacrosse.
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").