Arquebus
The arquebus ( ARK-ə-bus or AR-kwə-bus) (sometimes spelled harquebus, harkbus or hackbut; Italian Archibugio, Dutch haakbus, meaning "hook gun", or "hook tube") is an early muzzle-loaded firearm used in the 15th to 17th centuries. An arquebus was originally a gonne with hook, and later a matchlock firearm. Like its successor the musket, it is a smoothbore firearm, but was initially lighter and easier to carry.
It is a forerunner of the rifle and other longarm firearms. An improved version of the arquebus, the caliver, was introduced in the early 16th century. The word is derived from the English corruption of calibre as this gun was of standard bore, increasing combat effectiveness as troops could load bullets that would fit their guns (before, they would have to modify shot to fit, force it in, or cast their own before the battle).
Heavy arquebuses mounted on wagons were called arquebus à croc. These carried a ball of about 3.5 ounces (100 g).
Terminology
In the early 16th century, the term "arquebus" had a confusing variety of meanings. Some writers used it to denote any matchlock shoulder gun, referring to light versions as caliver and heavier pieces fired from a fork rest as musket. Others treated the arquebus and caliver synonymously, both referring to the lighter, forkless shoulder-fired matchlock. As the 16th century progressed, the term arquebus came to be clearly reserved for the lighter forkless weapon. When the wheel lock was introduced, wheel-lock shoulder arms came to be called arquebuses, while lighter, forkless matchlock and flintlock shoulder weapons continued to be called calivers. In the mid-17th century, the light flintlock versions came to be called fusils or fuzees.