pen vs kraal

pen and kraal both are nouns.

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

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

pen (noun)	kraal (noun)
female swan	a pen for livestock in southern Africa
a writing implement with a point from which ink flows	a village of huts for native Africans in southern Africa; usually surrounded by a stockade
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)	kraal (verb)
produce a literary work