The act defending and pretending form danger, attack, or injury.  It is anything employed to oppose attacks.  It is an argument in support for something.  It helps avoid substantial harm by means of dropping the chance to be hit or critically hit.

To better protect our forces and those of our associates and provides timely, objective and cogent military intelligence.  It is protection from harm; "sanitation is the best defense against disease".   In civil proceedings and criminal prosecutions under the common law, a defendant may raise a defense an attempt to avoid criminal or civil liability.

The leading Defense Industry association is the National Defense Industrials Association at America.  It provides an officially permitted forum for the exchange of information between Government and Industry.    The development is being by trained, innovative and support.  It has also many affiliated that progress of a business.