trioxide vs arsenic

trioxide and arsenic both are nouns.

Word	Noun	Adjective	Verb	Adverb
trioxide	Yes	No	No	No
arsenic	Yes	No	No	No

As nouns, arsenic is a hyponym of trioxide; that is, arsenic is a word with a more specific, narrower meaning than trioxide:

trioxide: an oxide containing three atoms of oxygen in the molecule
arsenic: a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide (rat poison) and weed killer

Other hyponyms of trioxide include arsenic trioxide, arsenous anhydride, arsenous oxide, ratsbane, white arsenic.

trioxide (noun)	arsenic (noun)
an oxide containing three atoms of oxygen in the molecule	a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and in various alloys; found in arsenopyrite and orpiment and realgar
	a white powdered poisonous trioxide of arsenic; used in manufacturing glass and as a pesticide (rat poison) and weed killer