Emily Dickinson Lexicon

WATCH, n. [Sax. wæcca, from wæcan, wæccan, to wake; Sw. vacht or vakt, watch, guard; vachta, to watch; Dan. vagt. It is from the same root as wake, – which see.]

1. Forbearance of sleep.
2. Attendance without sleep. All the long night their mournful watch they keep. – Addison.
3. Attention; close observation. Keep watch of the suspected man.
4. Guard; vigilance for keeping or protecting against danger. He kept both watch and ward. – – Spenser.
5. A watchman or watchmen; men set for a guard, either one person or more, set to espy the approach of an enemy or other danger, and to give an alarm or notice of such danger; a sentinel; a guard. He kept a watch at the gate. – Bacon. Ye have a watch; go your way, make it as sure as ye can. – Matth. xxvii.
6. The place where a guard is kept. He upbraids Iago, that he made him / Brave me upon the watch. – Shak.
7. Post or office of a watchman. As I did stand my watch upon the hill. – Shak.
8. A period of the night, in which one person or one set of persons stand as sentinels; or the time from one relief of sentinels to another. This period, among the Israelites, seems to have been originally four hours, but was afterward three hours, and there were four watches during the night. Hence we read in Scripture of the morning watch, and of the second, third, and fourth watch; the evening, watch commencing at six o'clock, the second at nine, the third at twelve, and the fourth at three in the morning. – Exod. xiv. Matth. xiv. Luke xii.
9. A small time-piece or chronometer, to be carried in the pocket or about the person, in which the machinery is moved by a spring.
10. At sea, the space of time during which one set or division of the crew remain on deck to perform the necessary duties. This is different in different nations. – Cyc. To be on the watch, to be looking steadily for some event.