Do you mean rule or ruler?

In engineering, a unified rule often refers to a standardized set of guidelines or principles that are applied consistently across various systems or processes to ensure uniformity and comparability. This concept can be particularly useful in fields like software engineering, where a unified rules engine might be used to manage and apply business rules consistently across different applications.

Ludwig Wittgenstein famously used rulers as an example in his discussion of language games in the Philosophical Investigations (1953). He pointed out that the standard meter bar in Paris was the criterion against which all other rulers were determined to be one meter long. However, there was no analytical way to demonstrate that the standard meter bar itself was one meter long. It could only be asserted as one meter as part of a language game.