Before revision: Definition There are multiple definitions of case studies, which may emphasize the number of observations (a small N), the method (qualitative), the thickness of the research (a comprehensive examination of a phenomenon and its context), and the naturalism (a "real-life context" is being examined) involved in the research.
After revision: Dephenomenon and its context), and the naturalism (a "real-life context" is being examined) involved in the research.