Definition of monion in English:

monion

(also monnion, munnion)

Pronunciation /ˈmʌnjən/

noun

rare, historical
  • A piece of armour covering either the shoulder or the whole of the upper arm.

Origin

Mid 17th century; earliest use found in Robert Loveday (1620/21–1656), translator. From French †mougnon piece of armour that covers the shoulder, †moignon, apparently a specifically application of moignon, †mougnon stump of an amputated limb.