N vs n

N and n both are nouns.

Word	Noun	Adjective	Verb	Adverb
N	Yes	No	No	No
n	Yes	No	No	No

As nouns, N and n are synonyms defined as:

N (noun)	n (noun)
the 14th letter of the Roman alphabet	the 14th letter of the Roman alphabet
(of a solution) concentration expressed in gram equivalents of solute per liter
a unit of force equal to the force that imparts an acceleration of 1 m/sec/sec to a mass of 1 kilogram; equal to 100,000 dynes
the cardinal compass point that is at 0 or 360 degrees
a common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas; constitutes 78 percent of the atmosphere by volume; a constituent of all living tissues