Tums vs gastric antacid

Tums and gastric antacid both are nouns.

Word	Noun	Adjective	Verb	Adverb
Tums	Yes	No	No	No
gastric antacid	Yes	No	No	No

As nouns, gastric antacid is a hypernym of Tums; that is, gastric antacid is a word with a broader meaning than Tums:

Tums: an antacid with active ingredient bismuth subsalicylate
gastric antacid: an agent that counteracts or neutralizes acidity (especially in the stomach)

Other hypernyms of Tums include alkaliser, alkalizer, antacid, antiacid.

Tums (noun)	gastric antacid (noun)
an antacid with active ingredient bismuth subsalicylate	an agent that counteracts or neutralizes acidity (especially in the stomach)