Wiktionary
n. (context military English) The firing of a gun after the last note of the retreat, signalling the lowering of the flag at sunset; the gun thus fired.
Usage examples of "evening gun".
But if, in the course of duty, you could require him to report aboard just after the evening gun, when I hope for an overland packet by courier, he may learn still more about the international situation.
But after quarters the longed-for drum would beat the retreat, tension would slacken, and hatred die away, so that by the time the evening gun roared out aboard the Admiral something like benevolence returned, and when he came forward to watch the dancing on the forecastle on warm, still, moonlit nights, or to see how the band was coming along, they would greet him very kindly.
My compliments to Mr Parker and you are to take the blue cutter to Dover with Bonden and six reliable men who deserve liberty until the evening gun.
He was tired, to the bone, and his shoulder ached and he wondered if his left arm would ever move free again, and the shadows lengthened on the carpet till he slept, not hearing the evening gun, or the door opening.
They talked on until well after the evening gun, supping together and going back over that voyage to Portugal in the Surprise during which Stephen would dimly have perceived the Berlings had he been on deck, and in which, after their going ashore at Lisbon, they heard of Sam's being ordained - Sam Panda, Jack's black love-child, begotten at the Cape - and they were still discussing his chances of a prelacy when the tender came alongside.
A small party, because for most of the frigate's people liberty had come to an end with yesterday's evening gun, and they had spent this forenoon striking camp - the hospital-tent had been an imposing affair with ample room for all the severe cases of scurvy and the other invalids - and carrying water, wood, dried fish and other stores aboard.
As things were, however, it was doubtful whether she would be able to do so before the evening gun.