1) guard, watch
    1a) a watching, keeping watch
        1a1) to keep watch
    1b) persons keeping watch, a guard, sentinels
    1c) of the place where captives are kept, a prison
    1d) of the time (of night) during which guard was kept, a watch
        i.e. a period of time during which part of the guard was on
        duty, and at the end of which others relieved them.  As the
        earlier Greeks divided the night commonly into three parts,
        so, previous to the exile, the Israelites also had three
        watches in a night; subsequently, however, after they became
        subject to the Romans, they adopted the Roman custom of
        dividing the night into four watches