Shield

"A shield is a type of personal armor, meant to intercept attacks, either by stopping projectiles such as arrows or by glancing a blow to the side of the shield-user. Shields vary greatly in size, ranging from large shields that protect the user's entire body to small shields that are mostly for use in hand-to-hand combat. Shields also vary a great deal in thickness; whereas some shields were made of thick wooden planking, to protect soldiers from spears and crossbow bolts, other shields were thinner and designed mainly for glancing blows away (such as a sword blow). In prehistory, shields were made of wood, animal hide, or wicker. In antiquity and in the Middle Ages, shields were used by footsoldiers and mounted soldiers. Even after the invention of gunpowder and firearms, shields continued to be used. In the 18th century, Scottish clans continued to use small shields, and in the 19th century, some non-industrialized peoples continued to use shields (e.g. Zulu warriors). In the 20th and 21st century, shields are used by military and police units that specialize in anti-terrorist action, hostage rescue, and siege-breaching. The term often refers to a device that is held in the hand/arm, as opposed to anarmoured suit or a bullet proof vest." words are straight from wikipedia. . http://en.wikipedia.org/wiki/Shield

I think shield and container could have similar meaning behind it. Both protect something. One by blocking something by holding a shield and the other blocking something by containing.