The words loop, loupe sound the same but have different meanings and spellings. Why do loop, loupe sound the same even though they are completely different words?
The answer is simple: loop, loupe are homophones of the English language.
To form into a loop.
A length of line, thread, ribbon, or other thin material that is curved or doubled over making an opening.
The opening formed by such a doubled line.
Something having a shape, order, or path of motion that is circular or curved over on itself.
A small magnifying glass usually set in an eyepiece and used chiefly by watchmakers and jewelers.
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").