Improving classroom teaching and learning requires both high-quality instructional materials and high-quality professional learning. Many professional learning stakeholders talk about the value of curriculum-based professional learning (CBPL) but there has been little consensus on what it is or how it fits within the larger field of professional learning. Learning Forward collaborated with other field leaders to develop this foundational resource that provides a clear definition of CBPL and the vocabulary and concepts around it. The definitions and alignment in this paper can streamline communication and research, promote ongoing learning, establish shared expertise, and enhance the impact of CBPL on student experiences and outcomes. A wide range of professional learning leaders can leverage it to assess their own PL programming and make updates to ensure it aligns with the features of effective CBPL. [This report was created with the Research Partnership for Professional Learning and Rivet Education.]