surcoat

 
Pronunciation: /ˈsəːkəʊt/

noun

historical
  • a loose robe worn over armour.
  • a similar sleeveless garment worn as part of the insignia of an order of knighthood.
  • an outer coat of rich material.

Origin:

Middle English: from Old French surcot, from sur 'over' + cot 'coat'