smoking compartment vs smoking carriage

smoking compartment and smoking carriage both are nouns.

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

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

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

Other synonyms of smoking compartment include smoker, smoking car.

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