Dagger
A dagger is a knife which is used to stab people. It has a double-edged blade, so it cannot be used for normal cutting like a knife.
Daggers are small, so they can often be hidden under the attacker's clothing and then suddenly produced.
They were also used in the Middle Ages for the infantry armies to defend or attack their opponents.
Some people like Julius Caesar were assassinated with a dagger.
Dagger Media
The Fairbairn–Sykes fighting knife, a modern-day dagger
A bronze dagger from Lorestan, Iran, 2600–2350 BCE
Bronze Age swords, Iranian Kurdistan, Museum of Sanandaj
Relief of akinakes, a type of ancient dagger, worn by an Achaemenid guard in Persepolis, Iran
Modern reproductions of medieval daggers. From left to right: Ballock dagger, Rondel dagger, and a Quillon dagger