equivalence

Short definition from Wiktionary

Noun

1. 1
   The condition of being equivalent or essentially equal.
2. 2
   An equivalence relation; ≡; ~
3. 3
   The relationship between two propositions that are either both true or both false.
4. 4
   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.
5. 5
   A Boolean operation that is TRUE when both input variables are TRUE or both input variables are FALSE, but otherwise FALSE; the XNOR function.
6. 6
   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.
7. 7
   The degree to which a term or text in one language is semantically similar to its translated counterpart.

Verb

1. 1
   To be equivalent or equal to; to counterbalance.