The words presser, pressor sound the same but have different meanings and spellings. Why do presser, pressor sound the same even though they are completely different words?
The answer is simple: presser, pressor are homophones of the English language.
One who presses clothes.
Any of various devices that apply pressure to a product in manufacturing or canning.
Causing an increase in blood pressure.
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").