The invasion of Poland gave rise to modern warfare that was literally powered by the internal combustion engine. Blitzkrieg (German, “lightning war” listen is an anglicised word describing all-motorised force concentration of tanks, infantry, artillery, combat engineers and air power, concentrating overwhelming force at high speed to break through enemy lines, and, once the lines are broken, proceeding without regard to its flank. Through constant motion, the blitzkrieg attempts to keep its enemy off-balance, making it difficult to respond effectively at any given point before the front has already moved on.
During the interwar period, aircraft and tank technologies matured and were combined with systematic application of the German tactics of infiltration and bypassing of enemy strong points. When Germany invaded Poland in 1939, Western journalists adopted the term blitzkrieg to describe this form of armoured warfare
Source: Wikipedia http://en.wikipedia.org/wiki/Blitzkrieg