folk vs folks

folk and folks both are nouns.

Word	Noun	Adjective	Verb	Adverb
folk	Yes	No	No	No
folks	Yes	No	No	No

As nouns, folk and folks are synonyms defined as:

Other synonyms of folk include common people.

folk (noun)	folks (noun)
the traditional and typically anonymous music that is an expression of the life of people in a community	your parents
people in general (often used in the plural)	people in general (often used in the plural)
a social division of (usually preliterate) people
people descended from a common ancestor