The words buccal, buckle sound the same but have different meanings and spellings. Why do buccal, buckle sound the same even though they are completely different words?
The answer is simple: buccal, buckle are homophones of the English language.
Of or relating to the cheeks or the mouth cavity.
A clasp for fastening two ends, as of straps or a belt, in which a device attached to one of the ends is fitted or coupled to the other.
An ornament that resembles this clasp, such as a metal square on a shoe or hat.
An instance of bending, warping, or crumpling; a bend or bulge.
To fasten with a buckle.
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").