aside vs by

aside is a noun but by is not a noun.

Word	Noun	Adjective	Verb	Adverb
aside	Yes	No	No	Yes
by	No	No	No	Yes

As adverbs, aside and by are synonyms defined as:

Other synonyms of aside include away.

aside (noun)	by (noun)
a line spoken by an actor to the audience but not intended for others on the stage
a message that departs from the main subject

aside (adverb)	by (adverb)
on or to one side	so as to pass a given point
out of the way (especially away from one's thoughts)	in reserve; not for immediate use
in reserve; not for immediate use
not taken into account or excluded from consideration
placed or kept separate and distinct as for a purpose
in a different direction