Source : Webster's Revised Unabridged Dictionary (1913)

Nova \No"va\ (n[=o]"v[.a]), n.; pl. L. {Nov[ae]} (-v[=e]), E.
   {Novas} (-v[.a]z). [L., fem. sing. of novus new.] (Astron.)
   A new star, usually appearing suddenly, shining for a brief
   period, and then sinking into obscurity. Such appearances are
   supposed to result from cosmic collisions, as of a dark star
   with interstellar nebulosities.

   Note: The most important modern nov[ae] are:

   {No"va Co*ro"n[ae] Bo`re*a"lis}[1866];

   {No"va Cyg"ni}[1876];

   {No"va An*dro"me*d[ae]}[1885];

   {No"va Au*ri"g[ae]}[1891-92];

   {No"va Per"se*i}[1901]. There are two nov[ae] called {Nova
      Persei}. They are:
   (a) A small nova which appeared in 1881.
   (b) An extraordinary nova which appeared in Perseus in 1901.
       It was first sighted on February 22, and for one night
       (February 23) was the brightest star in the sky. By July
       it had almost disappeared, after which faint surrounding
       nebulous masses were discovered, apparently moving
       radially outward from the star at incredible velocity.

Source : WordNet®

nova
     n : a star that ejects some of its material in the form of a
         cloud and become more luminous in the process
     [also: {novae} (pl)]

novae
     See {nova}