In zoological nomenclature, emendations are intentional alterations made to the spelling of taxon names.
[2][a] A justified emendation is different from a "mandatory change" only in that the latter is required by the Code, under Article 34.
[2][b] An unjustified emendation is different from an "incorrect subsequent spelling" in that the latter is an unintentional change, while an emendation is explicitly intentional, and in that an incorrect subsequent spelling is not automatically considered to be an available name.
An unjustified emendation has its own authorship or date (the author of the original spelling is not included in the attribution in any way).
[2][g] Under Article 33.2.3.1, if an unjustified emendation has erroneously been treated as if it had been justified, and used as the valid spelling of a taxon name by the majority of authors, then it is reclassified as a justified emendation and treated as such in perpetuity.