A use case is a sequence of related transactions performed by an actor in the system in a dialog. Or, to put it in English, a use case is a chunk of functionality.
kesi ya matumizi ni mlolongo wa shughuli kuhusiana na kazi kwa muigizaji katika mfumo katika dialog. Au, ili kuweka kwa Kiingereza, matumizi ya kesi ni chunk ya utendaji.