The phrase "power imbalance" means an uneven distribution of control or authority between people or groups. It suggests that one person or group has more power or influence than the other, creating an unequal dynamic. Full definition
The public policy rationale behind this is that there is inherent power imbalances between insurance companies and public litigants. (slaw.ca)
While discussing mediation, she expressed her concern that the mediation process can not address power imbalance in divorcing couples, especially when the husband was clearly the more powerful spouse. (divorcemed.com)
I think there has to be some sort of power imbalance for abuse to happen. (nakedpastor.com)