Which of the following words means to rectify or set something right?

The term that means to rectify or set something right is "redress." This word is often used in contexts where there is a need to correct a wrong or provide a remedy for an injustice. In legal and social contexts, redress is associated with compensating someone for harm or ensuring that grievances are addressed appropriately.

For instance, when one speaks of seeking redress, it involves taking steps toward resolution, whether that means altering a situation to be fairer or compensating someone for a loss. This concept extends beyond mere correction; it implies an active effort to restore balance or fairness.

In contrast, the other terms listed do not carry this specific meaning. "Regicide" refers to the act of killing a king, which is unrelated to correction or setting things right. "Shellac" is a type of finish or coating, often used in woodworking or crafts, and has no connection to rectification. "Shunt" typically involves redirecting something, such as a flow of electricity or traffic, but does not imply correction or redress in any form.