towel rail vs towel bar

towel rail and towel bar both are nouns.

Word	Noun	Adjective	Verb	Adverb
towel rail	Yes	No	No	No
towel bar	Yes	No	No	No

As nouns, towel rail and towel bar are synonyms defined as:

towel rail and towel bar: a horizontal bar a few inches from a wall for holding towels

towel rail (noun)	towel bar (noun)
a horizontal bar a few inches from a wall for holding towels	a horizontal bar a few inches from a wall for holding towels