smoking carriage vs smoking compartment

smoking carriage and smoking compartment both are nouns.

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

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

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

Other synonyms of smoking carriage include smoker, smoking car.

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