The terms "katana" and "samurai sword" are often used interchangeably, but there is a distinction between the two:

1. Katana: The katana is a specific type of Japanese sword that is characterized by its curved, single-edged blade, circular or squared guard (tsuba), and long grip (tsuka). It has a history dating back to feudal Japan and is closely associated with the samurai class. The katana typically has a length of around 60-80 centimeters (24-31 inches) with a curved blade, and it is traditionally worn with the cutting edge facing up.
2. Samurai Sword: The term "samurai sword" is a more general term that encompasses various types of swords used by samurai warriors in Japan. While the katana is the most well-known and iconic type of samurai sword, there are other types such as the wakizashi (a shorter companion sword) and the tanto (a dagger-like weapon). Together, the katana, wakizashi, and tanto form a set of swords known as the "daisho," which were traditionally worn by samurai.

In summary, the katana is a specific type of sword with distinct characteristics, while the term "samurai sword" is a broader term that refers to the swords associated with samurai warriors, including the katana, wakizashi, and tanto. However, due to the katana's prominence and popularity, it is often used as a shorthand to refer to a samurai sword in general.