Strike or Striking

Strike or Striking

Step 4: Striking

At this point, the round piece of metal is still a blank. This makes sense—it doesn't yet have the design and lettering that make it a coin.
The process of adding these items is called striking. The upset blanks go through the coining press. All at once, this machine strikes the pictures, amount, and mottoes onto both sides of the blank. Now it's a genuine United States coin!
http://www.usmint.gov/kids/coinnews/mintingProcess/images/coiningPress
Coining press stamps a blank into a coin. Once it's struck, the blank becomes a coin!