粤典 (words.hk)香港词
古時喺夜晚報時嘅公共服務；一晚分五更，每兩個鐘一更，晚上七點至九點係一更，直到淩晨三點至五點係五更；打更果陣會按時份用特定方式敲打鑼、鼓或木條，向居民報時。 (An ancient public service of time announcement by night watches. The night divines into 5 periods, every period is 2 hours, first period is 7:00-9:00pm, the fifth period is 03:00-05:00am. The night watches will patrol the village or town and hit a gong, drum or wooden clappers in specific pattern according to the time as an announcement.)
動詞用例
Announce period 3 at the start of night watch (means doing wrongly at the very start)