seltzer vs club soda

seltzer and club soda both are nouns.

Word	Noun	Adjective	Verb	Adverb
seltzer	Yes	No	No	No
club soda	Yes	No	No	No

As nouns, seltzer and club soda are synonyms defined as:

seltzer and club soda: effervescent beverage artificially charged with carbon dioxide

Other synonyms of seltzer include carbonated water, soda water, sparkling water.

seltzer (noun)	club soda (noun)
naturally effervescent mineral water	effervescent beverage artificially charged with carbon dioxide
effervescent beverage artificially charged with carbon dioxide