The shortest sword is often referred to as a "short sword" or "dagger." Short swords and daggers are typically characterized by their compact size and one-handed use. While specific measurements can vary, they generally have a blade length ranging from around 15 to 45 centimeters (6 to 18 inches). Some examples of short swords and daggers include:

1. Dirk: A Scottish traditional short sword or dagger with a straight blade, typically measuring around 30 to 45 centimeters (12 to 18 inches) in length.
2. Gladius: A Roman short sword with a double-edged blade, averaging around 45 to 60 centimeters (18 to 24 inches) in length.
3. Cinquedea: An Italian Renaissance short sword with a broad, double-edged blade, typically measuring around 30 to 45 centimeters (12 to 18 inches) in length.
4. Kris: A Southeast Asian dagger with a wavy blade, varying in length but often falling within the shorter range of 15 to 30 centimeters (6 to 12 inches).

It's important to note that the definition of a "short sword" can vary depending on cultural and historical contexts. Different cultures and time periods may have their own specific names and designs for short swords and daggers, each with their own unique characteristics and lengths.