The words cashew, cachou sound the same but have different meanings and spellings. Why do cashew, cachou sound the same even though they are completely different words?
The answer is simple: cashew, cachou are homophones of the English language.
A pastille used to sweeten the breath.
A tropical American evergreen tree (Anacardium occidentale) widely cultivated for its edible nutlike kernels.
The kidney-shaped seed of this tree, eaten after roasting.
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.