The words recede, reseed sound the same but have different meanings and spellings. Why do recede, reseed sound the same even though they are completely different words?
The answer is simple: recede, reseed are homophones of the English language.
To move back or away from a limit, point, or mark: waited for the floodwaters to recede.
To slope backward.
To become or seem to become fainter or more distant: Eventually, my unhappy memories of the place receded.
To withdraw or retreat.
To sow seeds again; to resow or replant.
Of a non-perennial plant, to produce seeds to ensure the following generation without human intervention; to self-sow.
To reset the input of an algorithm so as to ensure different results.
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").