shield

shield piece of defensive armor , worn on the arm or shoulder to ward off weapons during combat, used prior to the dominance of gunpowder. Originally for individual defense during hand-to-hand combat, it is the most primitive and universal item of defensive armor. Shields were made of hide or wood, often reinforced with metal, and could be round, oblong, or rectangular. As armies developed, soldiers carried matching shields to link together for fighting in formations, such as those used by Assyria (2500 BC). A soldier's body armor complemented his shield. Heavy infantry carried larger shields than did skirmishers, cavalry carried smaller shields, and bowmen often carried none. Modern riot police carry plastic shields for protection.

shield in the Middle Ages the armorial bearings of a knight were depicted on his shield; decorated shields, made for display rather than use, were often hung on walls in churches or other buildings as a memorial of a knight or noble. The word is recorded from Old English (in form scild) and is of Germanic origin; it comes ultimately from a base meaning ‘divide, separate’.

shield
1. A tunnel borer consisting of a conventional shield with thrust rams and erector system. The cutter head and support are inside the shield. This type of machine is usually employed in soils or variable materials, e.g. a sand—rock—gravel sequence.

2. See CRATON.