A more thorough explanation:

Definition: Collective measure refers to an activity that is carried out by multiple countries to achieve a common goal. This can be done in an ad hoc manner or through an institutionalized association.

Example: One example of a collective measure is the United Nations Security Council imposing economic sanctions on a country that violates international law. In this case, multiple countries come together to impose economic sanctions on a country to achieve a common goal of promoting international peace and security.

Another example of a collective measure is the Paris Agreement, which was signed by 195 countries to combat climate change. The agreement outlines a collective effort to reduce greenhouse gas emissions and limit global warming to below 2 degrees Celsius.

These examples illustrate how multiple countries can work together to achieve a common goal through a collective measure. By working together, countries can have a greater impact and achieve more than they would be able to on their own.