Glossary entry

v.
To set aside or modify any provision of the Code so as, e.g.
(1) to preserve or permit the use of a name as a valid name by removing the obstacles to such use, or
(2) to preserve the use of a name in a taxonomic sense that would otherwise be incorrect, or
(3) to deem a work to be published or available despite its not satisfying the normal criteria. In each case conservation is by a ruling of the Commission using its plenary power.

Source:
International Commission on Zoological Nomenclature (1999) International Code of Zoological Nomenclature. Fourth Edition. - International Trust for Zoological Nomenclature, XXIX + 306 pp.