From the early years of educational programming researchers considered procedural abstraction a key instrument of computational thinking and tried to understand the cognitive difficulties encountered through this concept. Defining procedures is promoted in renewed computing curricula in several countries. And yet, it is rarely acknowledged by more recent educational research. In this paper, we consider the fact that the delayed implementation of a mechanism for building procedures (known as definitions) within Scratch, a widely used programming environment for children, may have negatively impacted the focus within curricular content on this powerful idea. In our research, which is a part of a broader ScratchMaths (SM) research project, we set out to explore which factors play a role in upper primary pupils understanding and utilizing the concept of defining procedures as a common and inherent instrument of their programming. We present our observations from the project design schools and demonstrate how they guided the development of our SM pedagogic strategy for definitions.