The words mot, mow sound the same but have different meanings and spellings. Why do mot, mow sound the same even though they are completely different words?
The answer is simple: mot, mow are homophones of the English language.
A witty or incisive remark.
The place in a barn where hay, grain, or other feed is stored.
A stack of hay or other feed stored in a barn.
To cut down (grass or grain) with a scythe or a mechanical device.
To cut (grass or grain) from: mow the lawn.
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").