cataphract , n :
(military, historical) Defensive armour covering the entire body of a soldier and often the soldier's horse as well, especially the linked mail or scale armour of some eastern nations. (ichthyology, by extension, obsolete) An outer covering of some fish resembling armour or plate. [...] (military, historical) A soldier (especially a horseman) covered with a cataphract (etymology 1, sense 1).