"step" sounds atomic, while "rule" hints at internal structure, which in our case consists of mapping inputs to outputs using build instructions.
attempt to explain used and documented terminology, as well as how the declarative programming paradigm relates to building software. in the future one could highlight encouraged terms to shape future material into higher consistency.
following ideas found in Architecture of Gazelle[1] [1]: 56d35f8db0/Design.rst
56d35f8db0/Design.rst