A sword-breaker is a real-life weapon that is notched such that it can easily trap an opponent's sword. If the wielder is proficient enough, the sword-breaker can even trap axes and polearms, possibly disarming the opponent or allowing the user a strike with another weapon. Sometimes sword-breakers (called by some swordcatchers) are also sharpened and can be deadly in their own right in the real world, but this variety is not mentioned in the Wheel of Time.
In the world of the Wheel of Time, sword-breakers appear in use by Hurin and Juilin Sandar, perhaps suggesting the weapon is commonly favored by thief-takers. Hurin usually uses his sword-breaker in conjunction with a short sword or sometimes with a cudgel. Juilin's sword-breaker is described as "much like Hurin's but with short slots to either side of the long one," which he uses along with a bamboo staff. It is "like a short sword but unsharpened, its slots meant to catch a blade."
Juilin's sword-breaker may look more similar to this custom short sword/sword breaker which could be crafted to have "short slots to either side of the long one,"" a long slot in the center and the short to either side. This seems to fit the description of his sword-breaker better than one with a comb-like design along one or both sides.