The words re, ray sound the same but have different meanings and spellings. Why do re, ray sound the same even though they are completely different words?
The answer is simple: re, ray are homophones of the English language.
To send out as rays; emit.
Mathematics A straight line extending from a point. Also called half-line.
Slang Sunshine: Let's go to the beach and catch some rays.
A thin line or narrow beam of light or other radiant energy.
Music The second tone of the diatonic scale in solfeggio.
In reference to; in the case of; concerning.
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.