The words raise, rase, rays, raze, res sound the same but have different meanings and spellings. Why do raise, rase, rays, raze, res sound the same even though they are completely different words?
The answer is simple: raise, rase, rays, raze, res are homophones of the English language.
To move to a higher position; elevate: raised the loads with a crane. See Synonyms at lift.
To set in an upright or erect position: raise a flagpole.
To erect or build: raise a new building.
To cause to arise, appear, or exist: The slap raised a welt.
Variant of raze.
A thin line or narrow beam of light or other radiant energy.
A graphic or other representation of such a line.
A small amount; a trace: not a ray of hope left.
To level to the ground; demolish. See Synonyms at ruin.
To scrape or shave off.
Archaic To erase.
A thing; the particular thing; a matter; a point.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from the GNU version of the Collaborative International Dictionary of English and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.