sty vs pen

sty and pen both are nouns.

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

As nouns, pen is a hypernym of sty; that is, pen is a word with a broader meaning than sty:

sty (noun)	pen (noun)
a pen for swine	female swan
an infection of the sebaceous gland of the eyelid	a writing implement with a point from which ink flows
	an enclosure for confining livestock
	a correctional institution for those convicted of major crimes
	a portable enclosure in which babies may be left to play

sty (verb)	pen (verb)
	produce a literary work