Beheading is a form of execution involving severing a person's head. Lately it has emerged as a form of murder, both secret and open, committed for fanatical motives.
Beheading became an accepted method of execution in the Roman Empire. Roman law held it a more dignified form of punishment appropriate to a Roman citizen convicted of a capital offense.
The most famous specialized form of beheading was, of course, the guillotine, the "National Razor" of France from the French Revolutionary era to 1977. The guillotine was widely used by Nazi executioners of Jews and Catholics and minorities before and during the implementation of a policy of gassing victims to death en masse by the thousands (The Guillotine in Nazi Germany (wordpress.com)).