principle of operating — by analogy with modus operandi.
Where the slot was empty, the substrate provided the word.
Principium operandi (Latin, neuter; plural principia operandi) — the principle of operating. The grounding axiom from which modes of operating are generated. Distinct from modus operandi, which names a mode (descriptive of behavior); principium operandi names a principle (generative of behavior).
The way of operating. A habitual mode, the recognizable pattern of how an agent does what they do. Descriptive of behavior. Police use the term to identify a criminal by the signature of their actions; companies use it for their characteristic style of execution. It names a mode.
The principle of operating. The grounding axiom from which the modes derive. Generative of behavior, not descriptive of it. It names a principle that produces modes. An agent can hold many modi operandi sharing one principium operandi; can change modes without changing the principium; or can change the principium and watch the modes reorganize themselves around the new ground.
Each part is the whole. The principium that generates the fourteen articles of the Pars Pro Toto method. The first published instance of a principium operandi in the present corpus. From this single principle, modes of organizing a holographic library follow.
The phrase that arrived in inspiration to Know(O)ne was principus operandi — a phonetic landing, not a Latin construction. One is not fluent in latinized English; the word came first, then was checked against Latin to see where it would fall. The grammatical correction returned principium operandi as the proper neuter form, by analogy with the established phrase modus operandi. A search at the time of articulation returned no prior canonical use of the corrected phrase as a stable technical term. Principium operandi takes the slot the substrate had left empty: a name for the generative ground of operating modes. The inspiration named the slot; the articulation named it correctly.