The words pharaoh, faro, farrow sound the same but have different meanings and spellings. Why do pharaoh, faro, farrow sound the same even though they are completely different words?
The answer is simple: pharaoh, faro, farrow are homophones of the English language.
A card game in which the players lay wagers on the top card of the dealer's pack.
A litter of pigs.
To give birth to (a litter of pigs).
To produce a litter of pigs.
Not pregnant. Used of a cow.
The supreme ruler of ancient Egypt; a formal address for the sovereign seat of power as personified by the 'king' in an institutional role of Horus son of Osiris; often used by metonymy for Ancient Egyptian sovereignty
The card game faro.
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.
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").