smoking carriage vs smoking car

smoking carriage and smoking car both are nouns.

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

As nouns, smoking carriage and smoking car are synonyms defined as:

smoking carriage and smoking car: a passenger car for passengers who wish to smoke

Other synonyms of smoking carriage include smoker, smoking compartment.

smoking carriage (noun)	smoking car (noun)
a passenger car for passengers who wish to smoke	a passenger car for passengers who wish to smoke