The most important matter among several items that should be given top priority; something to be addressed or confirmed first (e.g., safety, project goals).
このプロジェクトでは安全が最優先事項だ。
Safety is the top priority in this project.
当面の最優先事項は人員の確保と設備の点検だ。
The immediate top priorities are securing personnel and inspecting equipment.
会議で最優先事項を明確にしてから作業を始めよう。
Let's clarify the top priorities in the meeting before starting the work.