The words balm, bomb sound the same but have different meanings and spellings. Why do balm, bomb sound the same even though they are completely different words?
The answer is simple: balm, bomb are homophones of the English language.
A chiefly Mediterranean perennial herb (Melissa officinalis) in the mint family, grown for its lemon-scented foliage, which is used as a seasoning or for tea. Also called lemon balm.
Any of several related plants in the mint family, such as the bee balm and the horse balm.
Any of various aromatic resins exuded from several trees and shrubs, especially the balm of Gilead (Commiphora) and related plants.
An aromatic salve or oil.
An explosive weapon detonated by impact, proximity to an object, a timing mechanism, or other means.
An atomic or nuclear bomb. Used with the.
Any of various weapons detonated to release destructive material, such as smoke or gas.
Football A long forward pass.
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").