The words Abel, able sound the same but have different meanings and spellings. Why do Abel, able sound the same even though they are completely different words?
The answer is simple: Abel, able are homophones of the English language.
In the Bible, the son of Adam and Eve who was slain by his elder brother, Cain.
Abel, Sir Frederick Augustus 1827-1902. British chemist noted for his research and writings concerning explosives. He invented cordite (1889) with Sir James Dewar.
Having sufficient power or resources to accomplish something: a singer able to reach high notes; a detergent able to remove stains.
Usage Problem Susceptible to action or treatment: The brakes were able to be fixed.
Especially capable or talented.
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").