National Union Catalog; a catalog issued by the Library of Congress containing a record of titles cataloged at the Library of Congress plus location of these titles in other libraries throughout the U.S. and Canada.

National Union Catalog. This multi-volume catalog in book or fiche format indicates which major U.S. and Canadian libraries own particular titles.

National Union Catalogue. The subset of the NBD that consists of bibliographic records that have holdings attached.

Nucs, or Nucleus Colonies, are small honey bee colonies created from larger colonies. The term refers both to the smaller size box and the colony of honeybees within it. The name is derived from the fact that a nuc hive is centered around a queen - the nucleus of the honey bee colony.

NATO-Ukraine Commission

referring to a nut (as in _Rifflea nucoides_ var. obesiformis)

nuclear