Source : Webster's Revised Unabridged Dictionary (1913)

Labarum \Lab"a*rum\, n.; pl. {Labara}. [L.]
   The standard adopted by the Emperor Constantine after his
   conversion to Christianity. It is described as a pike bearing
   a silk banner hanging from a crosspiece, and surmounted by a
   golden crown. It bore a monogram of the first two letters
   (CHR)

Source : WordNet®

labara
     See {labarum}