The words lead, led sound the same but have different meanings and spellings. Why do lead, led sound the same even though they are completely different words?
The answer is simple: lead, led are homophones of the English language.
A thin stick of such material.
To show the way to by going in advance.
To guide or direct in a course: lead a horse by the halter. See Synonyms at guide.
To serve as a route for; take: The path led them to a cemetery.
Past tense and past participle of lead1.
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").