gren·a·dier 
(grĕn′ə-dîr)
(grĕn′ə-dîr)n.
1.
a. A member of the British Grenadier Guards, the first regiment of the royal household infantry.
b. A soldier who is a member of a special corps or regiment.
c. A soldier equipped with grenades.
2. Any of various deep-sea fishes of the family Macrouridae, having a long tapering tail and lacking a tail fin. Also called rat-tail.
[French, from grenade, grenade; see GRENADE.]