Incomplete Planchet (Clip)
The image to the left is an example of a 1964 D
Lincoln Cent that has been struck on an
incomplete planchet.   Coins struck on incomplete
planchets are often referred to as "clipped".  The
term "clipped" is misleading because the missing
portion was not clipped off.  It was never there.  

When cent planchets are punched from metal
sheets, the punched area usually forms a perfectly
round planchet.   When sheets are misfed,
incomplete planchets can occur.  Curved "clips"
are created when a planchet is punched from an
area of a sheet that has already been punched.  
"Straight clips" and "Jagged clips" occur when
planchets are struck from overlapping sheets or
the end of a sheet.   Coins can also have "elliptical
clips" and "incomplete clips".  

The 1970 D cent below is another example of an
incomplete planchet.