"Core themes" refers to the main ideas or central topics that are frequently discussed or emphasized in a particular context such as a book, movie, or conversation. Full definition
This course includes an overview of the comprehensive examination process, the university's expectations of academic honesty and integrity, the three core themes of the examination, and the evaluation criteria. (onlineeducation.net)
Each year, I review a wide range of movies, studying them for their portrayal of core themes in positive psychology. (positivepsychologynews.com)
These highlights shouldn't be given in list form, but rather be structured around core themes. (interviewsuccessformula.com)