Culture: The customs, arts, social institutions, and achievements of a particular nation, people, or other social group (New Oxford American Dictionary)
Popular Culture: The totality of ideas, perspectives, attitudes, memes,[1] images and other phenomena that are deemed preferred per an informal consensus within the mainstream of a given culture (wikipedia).
Counterculture: A culture, especially of young people, with values or lifestyles in opposition to those of the established culture (answers.com).
Cultural Norms: Passed from one generation to the next, cultural norms are the shared, sanctioned, and integrated systems of beliefs and practices that characterize a cultural group. These norms foster reliable guides for daily living and contribute to the health and well-being of the group. As prescriptions for correct and moral behavior, cultural norms lend meaning and coherence to life, as well as the means to achieve a sense of integrity, safety and belonging. Thus, normative beliefs, together with related values and rituals, confer a sense of order and control upon aspects of life that might otherwise appear chaotic or unpredictable (answers.com).
Although I’ve been able to define these terms I feel that one of the best ways for me to understand culture is Practices of Looking. It seems to be the best source for me right now.