carriage vs smoking car

carriage and smoking car both are nouns.

Word	Noun	Adjective	Verb	Adverb
carriage	Yes	No	No	No
smoking car	Yes	No	No	No

As nouns, smoking car is a hyponym of carriage; that is, smoking car is a word with a more specific, narrower meaning than carriage:

carriage (noun)	smoking car (noun)
a vehicle with wheels drawn by one or more horses	a passenger car for passengers who wish to smoke
a railcar where passengers ride
a machine part that carries something else
a small vehicle with four wheels in which a baby or child is pushed around
characteristic way of bearing one's body