rota vs roster

rota and roster both are nouns.

Word	Noun	Adjective	Verb	Adverb
rota	Yes	No	No	No
roster	Yes	No	No	No

As nouns, roster is a hypernym of rota; that is, roster is a word with a broader meaning than rota:

rota: a roster of names showing the order in which people should perform certain duties
roster: a list of names

Other hypernyms of rota include roll.

rota (noun)	roster (noun)
a roster of names showing the order in which people should perform certain duties	a list of names