The words pelisse, police sound the same but have different meanings and spellings. Why do pelisse, police sound the same even though they are completely different words?
The answer is simple: pelisse, police are homophones of the English language.
A long cloak or outer robe, usually of fur or with a fur lining.
A woman's loose light cloak, often with openings for the arms.
The governmental department charged with the regulation and control of the affairs of a community, now chiefly the department established to maintain order, enforce the law, and prevent and detect crime.
A body of persons making up such a department, trained in methods of law enforcement and crime prevention and detection and authorized to maintain the peace, safety, and order of the community.
A body of persons having similar organization and function: campus police. Also called police force.
Police officers considered as a group.
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").