Asymmetry happens when one side is unequal to the other. Uma's eyes. Gramma's breasts. Any number times 2 then minus 1.
In Series-7-land, it refers to the dissemination of information relating to stocks and bonds and other securities wherein one set of players - maybe those closest to the company - get the information first, can trade or act on it, and then that information gets out to the rest of the world. This is illegal. Do not do this.