smell vs aroma

smell and aroma both are nouns.

Word	Noun	Adjective	Verb	Adverb
smell	Yes	No	Yes	No
aroma	Yes	No	No	No

As nouns, smell and aroma are synonyms defined as:

Other synonyms of smell include odor, odour, olfactory property, scent.

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

smell: the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form
aroma: a distinctive odor that is pleasant

smell (noun)	aroma (noun)
the act of perceiving the odor of something	any property detected by the olfactory system
any property detected by the olfactory system	a distinctive odor that is pleasant
the faculty that enables us to distinguish scents
the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form
the general atmosphere of a place or situation and the effect that it has on people

smell (verb)	aroma (verb)
become aware of not through the senses but instinctively
emit an odor
inhale the odor of; perceive by the olfactory sense
smell bad
have an element suggestive (of something)