Definition of "bordeaux"

Twelve fungicides; bordeaux mixture, strong, weak and with soap, bordeaux powder, modified eau celeste and ammoniacal copper carbonate, alone and with soap. As between the stronger and weaker bordeauxs an intermediate was [considered].

1908, Annual Report of the Vermont Agricultural Experiment Station, Burlington

The bordeauxs seem to have been the most efficient fungicides, with the proprietary lime-sulfur mixtures a close second.

1909, Reports of the Board of Trustees of the University of New Hampshire, volume 4, page 388

If these commercial materials are used to make a bordeaux or a copper-lime mixture for grape sprays, [...]

1961, John Roberts McGrew, George Willis Still, Control of Grape Diseases and Insects in the Eastern United States

For under Charlemagne, in particular, this industry greatly expanded, as the wine masters of Gaul began to produce their own high quality burgandies and bordeauxes in the very regions in which those modern wines now derive their names.

2006, Gene W. Heck, Charlemagne, Muhammad, and the Arab Roots of Capitalism