The words choler, collar sound the same but have different meanings and spellings. Why do choler, collar sound the same even though they are completely different words?
The answer is simple: choler, collar are homophones of the English language.
One of the four humors of ancient and medieval physiology, thought to cause anger and bad temper when present in excess; yellow bile.
Obsolete The quality and condition of being bilious.
The part of a garment that encircles the neck.
A restraining or identifying band of leather, metal, or plastic put around the neck of an animal.
The cushioned part of a harness that presses against the shoulders of a draft animal.
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.