Resonance

Resonance is the combination of Surges amongst Surgebinders which has unique effects. In essence, it is a branch of effects which manifest within a person who bears at least two powers. The effect does not directly affect how the powers creating it are used. It's the interaction between - and side effects of - the combination of two or more magic abilities, which don't necessarily have to be from different Shards or even magic systems. This has been confirmed by Brandon and it is cosmere-wide mechanics when a Nahel bonded individual has access to two different powers.