定案 is a separable verb (离合词) meaning 'to reach a verdict' or 'to finalize a decision'. As a v.o. compound, 定 can be separated from 案 by aspect particles (了, 过), measure words, or durations — e.g., 定了案 ('reached a verdict'), 定过几次案 ('finalized the decision several times'). The object of the decision is typically introduced by a preposition or placed before the verb. Although the gloss also includes noun senses ('verdict', 'final decision'), this row's POS is strictly verb–object; the noun usage is a related but grammatically distinct function.