A sergeant is a rank — not the top, not the bottom — in the army, the air force, or the police, and the person who holds that rank. Sergeants often train people, keep daily order, and carry out what officers decide. In many armies they are the experienced backbone: close to the soldiers, trusted with the work on the ground. The exact rung is not the same in every country, so a sergeant in an American film is not a perfect copy of a Taiwan 中士, but that is the nearest everyday hook. People shorten it to Sarge when they speak to one. The spelling is a trap: it looks like ser-geant, but it is said SAR-jənt. You do not sound a hard g. That is because the word came through Old French, where the sound softened, from a Latin word meaning serving. It is a doublet of servant — first someone who serves, then a serving soldier, then a rank. Though actually, older English also used sergeant for certain court and city officers (a sergeant-at-arms, a sergeant-at-law), so not every sergeant in an old book is a soldier. There is even a striped fish nicknamed sergeant, because the stripes reminded people of rank badges. For learners, the rank is the meaning that matters.