Source : Webster's Revised Unabridged Dictionary (1913)

National \Na"tion*al\ (?; 277), a. [Cf. F. national.]
   1. Of or pertaining to a nation; common to a whole people or
      race; public; general; as, a national government,
      language, dress, custom, calamity, etc.

   2. Attached to one's own country or nation.

   {National anthem}, a popular song or hymn which has become by
      general acceptance the recognized musical expression of
      the patriotic sentiment of a nation; as, ``God save the
      King'' is called the national anthem of England.

   {National bank}, the official common name of a class of
      banking corporations established under the laws of the
      United States.

   {National flag}. See under {Flag}.

   {National guard}, a body of militia, or a local military
      organization, as in Paris during the French Revolution, or
      as certain bodies of militia in other European countries
      and in the United States.

   {National salute}, a salute consisting of as many guns as
      there are States in the Union. [U.S.]

Source : WordNet®

national anthem
     n : a song formally adopted as the anthem for a nation