Cold Duck was an alcoholic beverage invented by Harold Borgman, the owner of Pontchartrain Wine Cellars in Detroit on Earth, in 1937. The recipe was based on a traditional German custom of mixing all the dregs of unfinished wine bottles with champagne. The wine he produced was given the name Kaltes Ende ("cold end" in German), until it was humorously altered to the similar sounding term Kalte Ente meaning "cold duck".
Leonard McCoy and Montgomery Scott included this drink in their "drinking alphabet". (TOS novel: Uhura's Song)