Esi
abbr. 紧急停止指示器（Emergency Stop Indicator）；外部指定索引（Externally Specified Index）
🗣️ 情景例句
Take care, and have a nice flight.
请保重！祝你一路顺风！
Don't mind him.
别理他！
Yes. B-double O-K, book.
好的。B-双写O-K，book（书）。