heroin vs hell dust

heroin and hell dust both are nouns.

Word	Noun	Adjective	Verb	Adverb
heroin	Yes	No	No	No
hell dust	Yes	No	No	No

As nouns, hell dust is a hyponym of heroin; that is, hell dust is a word with a more specific, narrower meaning than heroin:

heroin: a narcotic that is considered a hard drug; a highly addictive morphine derivative; intravenous injection provides the fastest and most intense rush
hell dust: street names for heroin

Other hyponyms of heroin include big H, nose drops, scag, skag, smack, thunder.

heroin (noun)	hell dust (noun)
a narcotic that is considered a hard drug; a highly addictive morphine derivative; intravenous injection provides the fastest and most intense rush	street names for heroin