This is the 7099th most frequent Korean word.
정할
"To decide" or "to determine."
In this sentence, '정할' is used as a verb meaning 'to decide' or 'to set', reflecting the need to agree on a specific time.
우리는 만날 시간을 정할 필요가 있습니다.
We need to decide on a time to meet.
Here, '정할' is part of '정해야', indicating the necessity to 'set' or 'determine' the travel plan.
여행 계획을 정해야 하는데 무엇을 우선할까요?
We need to decide on the travel plan; what should we prioritize?
In this context, '정할' is used in its infinitive form '정하는', which means 'setting' or 'establishing' new rules.