Equivalences meaning : The condition of being equivalent or essentially equal. An equivalence relation; ≡; ~ The relationship between two propositions that are either both true or both false. The quantity of the combining power of an atom, expressed in hydrogen units; the number of hydrogen atoms can combine with, or be exchanged for; valency. A Boolean operation that is TRUE when both input variables are TRUE or both input variables are FALSE, but otherwise FALSE; the XNOR function. A number in intersection theory. A positive-dimensional variety sometimes behaves formally as if it were a finite number of points; this number is its equivalence. The degree to which a term or text in one language is semantically similar to its translated counterpart.