The words load, lode, lowed sound the same but have different meanings and spellings. Why do load, lode, lowed sound the same even though they are completely different words?
The answer is simple: load, lode, lowed are homophones of the English language.
A responsibility regarded as oppressive.
A weight or mass that is supported: the load on an arch.
The overall force to which a structure is subjected in supporting a weight or mass or in resisting externally applied forces.
Something that is carried, as by a vehicle, person, or animal: a load of firewood.
The metalliferous ore that fills a fissure in a rock formation.
A vein of mineral ore deposited between clearly demarcated layers of rock. Also called lead1.
A rich source or supply.
Simple past tense and past participle of low.
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").