Emplacement. A position made of earth or sandbags from which a machine gun is fired. It is supposed to be invisible to the enemy. They generally blow it up in the course of a couple of days, just by luck, of course.
Entrenching Tool. A spade-like tool for digging hasty entrenchments. It takes about a week to dig a decent hole with it, so "hasty" must have another meaning.
"Equipment on." Put on equipment for drill or parade.
Escort. A guard of soldiers who conduct prisoners to different points. Tommy is just as liable to be a prisoner as an escort.
"Estaminet." A French public house, or saloon, where muddy water is sold for beer.
F
Fag. Cigarette. Something Tommy is always touching you for, "Fag issue." Army issue of cigarettes, generally on Sunday.
Fatigue. Various kinds of work done by Tommy while he is "resting."
"Fed up." Disgusted; got enough of it -- as the rich Mr. Hoggenheimer used to say, "Sufficiency."
Field Dressing. Bandages issued to soldiers for first aid when wounded. They use them for handkerchiefs and to clean their rifles.