Commandos (United Kingdom) in the context of United States Army Rangers

A combat knife is a fighting knife designed for military use and primarily intended for hand-to-hand or close combat fighting.

Since the end of trench warfare, most military combat knives have been secondarily designed for utility use (clearing foliage, chopping branches for cover, opening ammunition crates, etc.) in addition to their original role as close-quarter combat weapons, and may be referred to as "fighting-utility knives." On the other hand, military knives that are intended primarily for use in a role other than combat are typically referred to by their primary role, such as "utility knife" or "survival knife".

The Fairbairn–Sykes fighting knife is a double-edged fighting knife resembling a dagger or poignard with a brass or wooden foil grip. It was developed by William Ewart Fairbairn and Eric Anthony Sykes in Shanghai based on ideas that the two men had while serving on the Shanghai Municipal Police in China before World War II.

The F-S fighting knife was made famous during World War II when issued to British Commandos, the Airborne Forces, the Special Air Service (SAS) and many other units, especially for the Normandy landings in June 1944. With its acutely tapered, sharply pointed blade, the F-S fighting knife is frequently described as a stiletto, a weapon optimised for thrusting, although the F-S knife can be used to inflict slash cuts upon an opponent when its cutting edges are sharpened according to specification. The Wilkinson Sword Company made the knife with minor pommel and grip design variations.