The words mead, meed sound the same but have different meanings and spellings. Why do mead, meed sound the same even though they are completely different words?
The answer is simple: mead, meed are homophones of the English language.
An alcoholic beverage made from fermented honey and water.
Archaic A meadow.
A fitting recompense.
Archaic A merited gift or wage.
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").