dogwatch

名词 dogwatch:

1. either of two short watches: from 4-6 pm or 6-8 pm

dog.watch

n.（名词）
Nautical Either of two short periods of watch duty, from 4 to 'p.m. or ' to 8 p.m.
【航海】 二时班：下午 4时到'时或 下午 '时到8时的两个值班时间之一
A late night shift.
夜班

来源：
Probably from dog-sleep [a light or interrupted sleep]
可能源自 dog-sleep [一段浅睡或被打断的睡眠]