Definition of "watch" []

• To look or observe attentively or carefully; be closely observant: watching for trail markers. (verb-intransitive)
• To look and wait expectantly or in anticipation: watch for an opportunity. (verb-intransitive)
• To act as a spectator; look on: stood by the road and watched. (verb-intransitive)
• To stay awake at night while serving as a guard, sentinel, or watcher. (verb-intransitive)
• To stay alert as a devotional or religious exercise; keep vigil. (verb-intransitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In a man-of-war, and in some merchantmen, this alternation of watches is kept up throughout the twenty-four hours; but our ship, like most merchantmen, had “all hands” from twelve o’clock till dark, except in bad weather, when we had “watch and watch."
• "If a watch, it can be said, "Your friends are growing a little suspicious of you, and, after due deliberation, they have determined to a place _a watch_ upon you.""
• "When a spy was sent from Ghadames to watch the Shânbah and their approaches round the country, on the eve of my departure from that place, people went up a ruined tower, situated on a high ground, and apparently built specially for the purpose, _to watch_ the return of the spy."