The words raid, rayed sound the same but have different meanings and spellings. Why do raid, rayed sound the same even though they are completely different words?
The answer is simple: raid, rayed are homophones of the English language.
A surprise attack by a small armed force.
A sudden forcible entry into a place by police: a raid on a gambling den.
An entrance into another's territory for the purpose of seizing goods or valuables.
A predatory operation mounted against a competitor, especially an attempt to lure away the personnel or membership of a competing organization.
Simple past tense and past participle of ray.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from Wiktionary, Creative Commons Attribution/Share-Alike License and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.