The words cubical, cubicle sound the same but have different meanings and spellings. Why do cubical, cubicle sound the same even though they are completely different words?
The answer is simple: cubical, cubicle are homophones of the English language.
Cubic.
Of or relating to volume.
Of or pertaining to a cube.
Cubic.
A small compartment, as for work or study.
A small sleeping compartment, especially within a dormitory.
A bedroom; a chamber.
A loding room; esp., a sleeping place partitioned off from a large dormitory.
Definitions from The American Heritage® Dictionary of the English Language, 5th Edition., from The Century Dictionary., 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.
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").