pen vs rodeo

pen and rodeo both are nouns.

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

As nouns, rodeo is a hyponym of pen; that is, rodeo is a word with a more specific, narrower meaning than pen:

pen (noun)	rodeo (noun)
female swan	an exhibition of cowboy skills
a writing implement with a point from which ink flows	an enclosure for cattle that have been rounded up
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

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