In policing, COP and POP are acronyms for types of police work.
COP stands for Community-Oriented Policing. This type of police work involves regular interactions with the community which fosters positive relationships between community members and police. The theory suggests that a community member who is familiar with the police is more likely to come forward when something nefarious happens in their neighborhood. Similarly, the police are more likely to make good calls when they know the people in the area and are familiar with the dynamics at play.
POP stands for Problem-Oriented Policing. This type of police work relies on the theory that the quickest way to help the most number of people is by applying proven tactics that generally solve issues. While this kind of police work does not take into consideration personalized approaches to a community, it saves officers time which can be spent elsewhere.
In reality, most scholars argue that these different kinds of policing may each have benefits and are best applied by first analyzing the kinds of issues a particular area faces and tailoring police work depending on the outcomes desired in that community.