Source : Webster's Revised Unabridged Dictionary (1913)

Fusileer \Fu"sil*eer"\, Fusilier \Fu"sil*ier"\, n. [F. fusilier,
   fr. fusil.] (Mil.)
   (a) Formerly, a soldier armed with a fusil. Hence, in the
       plural:
   (b) A title now borne by some regiments and companies; as,
       ``The Royal Fusiliers,'' etc.

Source : WordNet®

fusilier
     n : (formerly) a British infantryman armed with a light
         flintlock musket