watchman

Etymology

From Middle English waccheman, equivalent to watch + -man.

noun

1. One set to watch; a person who keeps guard, especially one who guards a building, or the streets of a city, by night.
   The visits of the watchman to that (then) obscure and ill-inhabited neighborhood were more regulated by his indolence than his duty; and Clarence knew that it would be in vain to listen for his cry or tarry for his assistance. 1829, Edward Bulwer Lytton, chapter XVIII, in The Disowned
   Well, it so happened that Stine and the cook were sitting in their room one evening, mending and darning their things; it was near bedtime, for the watchman had already sung out "Ten o'clock," but somehow the darning and the sewing went on very slowly indeed[.] 1886, Peter Christen Asbjørnsen, translated by H.L. Brækstad, Folk and Fairy Tales, page 8
   Watchmen are stationed continuously at each end of the bridge, and the main spans are patrolled twice during the night. 1950 March, H. A. Vallance, “On Foot Across the Forth Bridge”, in Railway Magazine, page 149