Daiklave

In Exalted, a Diaklave is an ornate, enormous blade make from an alloy of one of the magical materials. They are enchanted to be lighter in the hand of their attuned wielder than they really are. Each diaklave is a unique wonder, with a name, and is treated by its Exalted bearer as a treasured friend.

Unfortunately, this hasn't always been represented in the rules. A diaklave isn't much more than a +2 sword equivalent in the earlier editions, with little variation from one to the next. Many players - and NPCs - didn't bother naming their weapons. You had a jade diaklave, speed 4 acc 3 dam 6/2L def 2 attune 5, same as all the others. The book on artifacts gave guidelines on rating artifact powers, but gave little advice on combining them, even as it gave examples of diaklaves with extra powers. There was some effort in the Infernals book to introduce additional enchantments to place on an artifact weapon - chip damage on a parry, ignoring hardness, being more deadly at night, even having their own charms. That idea got expanded on in third edition, where every artifact weapon is given its own unique charms called Evocations, solving the uniqueness problem at last.

Diaklave is, specifically, the term for swords of this nature. The general term is 'artifact weapon.' For axes, you have Grimcleavers, for maces and hammers you have Goremauls, bows are Powerbows, and a few others. Diaklaves are the most iconic, though, in the way that swords usually are. They uniquely have several subtypes - short diaklaives, grand diaklaves, reaper diaklaves, etc.

Diaklaves contribute greatly to the weeaboo reputation of Exalted. A pair of cute girls in kimonos duking it out with swords bigger than they are is very much in Exalted's aesthetic.