Culture refers to a shared patterns of seeing, thinking, and acting. If we both part of a culture or sub-culture, we share certain ways of interpreting, understanding, and behaving.
The term culture thus differs from the term society in instructive ways. Society simply refers to a large group of people. To say something is a "social problem," for example, means generally that there is an issue among a group. To say something is a "cultural problem" means that the issue specifically has to do with interpreting, defining, judging, or acting.