cataphract

n. ancient Greek warship; scaled suit of armor worn by ancient Romans; Roman soldier wearing a suit of armor; (Zoology) system of hard scales that cover the bodies of some fishes and reptiles

A cataphract (from the Greek κατάφρακτος kataphraktos, plural kataphraktoi, literally meaning (very) "behind barriers", "behind a fence", "protected") was a form of heavy cavalry used by nomadic eastern Iranian tribes and dynasties and later Greeks and Latin-speaking peoples. Historically the cataphract was a heavily armed and armoured cavalryman who saw action from the earliest days of Antiquity up through the High Middle Ages. Originally, the term cataphract referred to a type of armour worn to cover the whole body and that of the horse. Eventually the term described the trooper himself.
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Noun
1. armor that protects the wearer's whole body
(synonym) body armor, body armour, suit of armor, suit of armour, coat of mail
(hypernym) armor, armour
(hyponym) bulletproof vest
(part-meronym) armet

(n.)
The armor or plate covering some fishes.
  

(n.)
Defensive armor used for the whole body and often for the horse, also, esp. the linked mail or scale armor of some eastern nations.
  

(n.)
A horseman covered with a cataphract.