j vs J

j and J both are nouns.

Word	Noun	Adjective	Verb	Adverb
j	Yes	No	No	No
J	Yes	No	No	No

As nouns, j and J are synonyms defined as:

j (noun)	J (noun)
the 10th letter of the Roman alphabet	the 10th letter of the Roman alphabet
	a unit of electrical energy equal to the work done when a current of one ampere passes through a resistance of one ohm for one second