In the context of text processing, the process or result of establishing whether two text elements are identical in some respect.

the recognizable identity of the reality experienced and symbolized on various levels of differentiation

Two Boolean expressions are equivalent if they they have the same set of models.

Two nodes are equivalent if they have the same node type and same node name. Also, if the nodes contain data, that must be the same. Finally, if the nodes have attributes then collection of attribute names must be the same and the attributes corresponding by name must be equivalent as nodes. Two nodes are deeply equivalent if they are equivalent, the child node lists are equivalent are equivalent as NodeList objects, and the pairs of equivalent attributes must in fact be deeply equivalent. Two NodeList objects are equivalent if they have the same length, and the nodes corresponding by index are deeply equivalent. Two NamedNodeMap objects are equivalent if they are have the same length, they have same collection of names, and the nodes corresponding by name in the maps are deeply equivalent. Two DocumentType nodes are equivalent if they are equivalent as nodes, have the same names, and have equivalent entities and attributes NamedNodeMap objects.

the comparability of two or more parallel measures that have been designed to assess the same aspect of teaching and to yield similar evaluation results regardless of the measure used or the scoring/rating procedure applied (e.g., two different social studies textbook chapters to be analyzed as part of a semi-structured interview; two essay questions on teaching the same content area in math, but to different types of student groups). See Comparability.

A way of saying that two things are treated the same according to a definition of equality. In sensemaking, notions of equivalence are important for governing retrieval based on assumed similarity of meaning. For example, a matcher may treat two words as equivalent if they are synonyms. The notion of equivalence can be applied to any kind of representation, including terms, phrases and subgraphs. Two phrases may be equivalent if they express the same relationships between words that are synonyms. See term-equivalence dictionary and subgraph equivalence.

In mathematics, and specifically in measure theory, equivalence is a notion of two measures being "the same".

a state of being essentially equal or equivalent; equally balanced; "on a par with the best"

essential equality and interchangeability

In quantitative verse, the rule that two short syllables equal one long syllable. See mora.