The Collaborative International Dictionary of English v.0.48:

Noyade \No`yade"\, n. [F., fr. noyer to drown, L. necare to
   kill.]
   A drowning of many persons at once, -- a method of execution
   practiced at Nantes in France during the Reign of Terror, by
   Jean Baptiste Carrier.
   [Webster 1913 Suppl.]