Ruddy—Same as bloody, but not quite so bad.
Sandbag—A bag which is filled with mud and used for building the parapet.
Sentry go—Time on guard in the front trench, or at rest at headquarters.
Shell hole—A pit made by the explosion of a shell.
Souvenir—Any kind of junk picked up for keepsakes. Also used as a begging word by the French children.
Stand to—Order for all men to stand ready in the trench in event of a surprise attack, usually at sundown and sunrise.
Stand down—Countermanding "stand to."
Stokes—A bomb weighing about eleven pounds usually thrown from a mortar, but sometimes used by hand.
Strafing—One of the few words Tommy has borrowed from Fritz. To punish.
Suicide club—The battalion bombers.