equivalence
This term describes a state of balance where two different things function as the same thing in a specific context. It suggests a functional symmetry rather than a literal identity; the items are not the same object, but they carry the same weight or effect. This is common in mathematics, linguistics, and finance to describe a trade-off or a translation that preserves the original intent. In social or legal contexts, the word carries a sense of fairness and parity. It is often used to argue that a substitute is just as valid as the original, shifting the focus from the nature of the things themselves to the value they represent.
Countable when referring to a specific instance of equality between two things (an equivalence). Uncountable when referring to the general principle or state of being equal.