What is the 'four pillars' mean?

The "four pillars" typically refer to foundational principles or components that support a broader concept, depending on the context. In various fields, such as education, sustainability, and economics, these pillars represent essential elements that contribute to stability and success. For example, in education, the four pillars might emphasize learning to know, learning to do, learning to live together, and learning to be. The specific meaning can vary, so it's essential to consider the context in which the term is used.