Short sword

A short sword (also shortsword), is a light, piercing melee weapon.

Description
In essence, this weapon is a smaller version of the longsword but longer than a dagger or dirk, having many of the same parts including a generally double-edged blade, cross-guard, grip, and pommel. The blade is typically from 12 to 20 inches (30 to 50 cm) long with a sharp point. An average short sword costs 10gp and weighs 2lbs (0.9kg). First edition D&D defined the short sword as "all pointed cutting & thrusting weapons with blade length between 15in (38cm) and 24in (61cm)."

Weaponology
Short swords are standard issue to many different types of soldiers. Archers favor this weapon for use when the combat range narrows to a point such that their bows are no longer effective. Many warriors, including fighters, barbarians, paladins, and rangers carry these as a secondary weapon for use in the off-hand. Smaller races will often use short swords as their primary weapon. Light and maneuverable, yet able to provide many different types of attacks, it is arguably the most common weapon on the battlefield. The versatile short sword requires training to use effectively and is therefore classified as a martial weapon. It is light enough to be used with finesse but its smaller size means it deals less damage than a heavier blade. Because it is a light blade, it makes a good choice for the off-hand in two-weapon fighting styles.

Realmslore
These blades are common throughout all parts of Toril, including but not limited to Faerun, Kara-Tur, and Zakhara. As usual, depending upon what part of Toril you're standing in, they are known by different colloquial names. In Faerun in addition to being known as a short sword you may also hear the terms gladius or warsword. In the eastern lands of Kara-Tur, they can be found by the names of wakizashi or the exotic butterfly sword. Finally, in the areas of Zakhara they may be referred to as falcata or bast.