resid vs residual oil

resid and residual oil both are nouns.

Word	Noun	Adjective	Verb	Adverb
resid	Yes	No	No	No
residual oil	Yes	No	No	No

As nouns, resid and residual oil are synonyms defined as:

resid and residual oil: oil products that remain after petroleum has been distilled

resid (noun)	residual oil (noun)
oil products that remain after petroleum has been distilled	oil products that remain after petroleum has been distilled