A longsword is a type of European sword characterized as having a cruciform hilt with a grip for two-handed use.
A western-style/European sword used with two hands, typically from stomach height to head height. Any sword larger/taller than the wielder is a greatsword. Any sword that can reasonably be held with only one hand is a short sword. Swords with a particularly wide blade (single handed or two handed alike) are broadswords.