A dagger is a fighting knife with a very sharp point and usually one or two sharp edges, typically designed or capable of being used as a cutting or thrusting weapon. Daggers have been used throughout human history for close combat confrontations, and many cultures have used adorned daggers in ritual and ceremonial contexts. The distinctive shape and historic usage of the dagger have made it iconic and symbolic. A dagger in the modern sense is a weapon designed for close-proximity combat or self-defense; due to its use in historic weapon assemblages, it has associations with assassination and murders. Double-edged knives, however, play different sorts of roles in different social contexts.
The Fairbairn–Sykes fighting knife, a modern-day dagger
A bronze dagger from Lorestan, Iran, 2600–2350 BCE
A Neolithic dagger from the Muséum de Toulouse
Pre-Roman Iberian iron dagger forged between the middle of the 5th and the 3rd century BC
A fighting knife has a blade designed to most effectively inflict injury in close-quarters physical confrontations. The combat knife and the trench knife are examples of military fighting knives.
An assortment of fighting knives
Top: Bowie Knife c. 1850s Bottom: Naval Bowie Knife c. 1860s
M1918 Trench Knife
U.S. Marine KA-BAR Knife