The words hole, whole sound the same but have different meanings and spellings. Why do hole, whole sound the same even though they are completely different words?
The answer is simple: hole, whole are homophones of the English language.
A hollowed place in something solid; a cavity or pit: dug a hole in the ground with a shovel.
An opening or perforation: a hole in the clouds; had a hole in the elbow of my sweater.
Sports An opening in a defensive formation, such as the area of a baseball infield between two adjacent fielders.
A fault or flaw: There are holes in your argument.
on the whole Considering everything: on the whole, a happy marriage.
Containing all components; complete: a whole wardrobe for the tropics.
Not divided or disjoined; in one unit: a whole loaf.
Constituting the full amount, extent, or duration: The baby cried the whole trip home.
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").