The words blew, blue sound the same but have different meanings and spellings. Why do blew, blue sound the same even though they are completely different words?
The answer is simple: blew, blue are homophones of the English language.
Past tense of blow1.
Past tense of blow3.
The hue of that portion of the visible spectrum lying between green and indigo, evoked in the human observer by radiant energy with wavelengths of approximately 420 to 490 nanometers; any of a group of colors that may vary in lightness and saturation, whose hue is that of a clear daytime sky; one of the additive or light primaries; one of the psychological primary hues.
A pigment or dye imparting this hue.
Bluing.
An object having this hue.
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").