The SERNA Conceptual Standard for Blended Learning in K-12 Education: Definitions, Relationships, and Theoretical Integration (SCS-BLK)

**Background:** Blended learning, the strategic integration of face-to-face and online instruction, has become a dominant model in K-12 education. However, the field is characterized by "terminological chaos," with terms like "hybrid learning," "flipped classroom," "personalized learning," and "technology-enhanced instruction" often used interchangeably or without precise operational distinctions. **Problem:** This conceptual fragmentation prevents the development of standardized implementation protocols and limits the ability to measure the impact of specific blended models on student achievement and engagement. Specifically, the "Teacher-Led" vs. "Student-Controlled" balance remains modeled inconsistently. **Objective:** To establish the SERNA Conceptual Standard (SCS-BLK), providing canonical definitions and a testable socio-pedagogical model for blended learning in K-12 settings. **Approach:** A systematic review of over 400 peer-reviewed articles was conducted, synthesizing evidence from instructional design, educational psychology, and K-12 policy analysis. **Contributions:** This standard defines 12 canonical terms, establishes the "Integrated Learning Synchrony (ILS) Model," and proposes 10 falsifiable hypotheses for future research. **Conclusions:** SCS-BLK provides the theoretical infrastructure to transition blended learning research from descriptive platform evaluations to predictive modeling of instructional alignment and student success.