pen nib vs nib

pen nib and nib both are nouns.

Word	Noun	Adjective	Verb	Adverb
pen nib	Yes	No	No	No
nib	Yes	No	No	No

As nouns, pen nib and nib are synonyms defined as:

pen nib (noun)	nib (noun)
the writing point of a pen	horny projecting mouth of a bird
	the writing point of a pen