A goedendag (also rendered godendac, godendard, godendart, and sometimes conflated with the related plançon) was a weapon originally used by the militias of Medieval Flanders in the 14th century, notably during the Franco-Flemish War.
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The name "goedendag" derives from Dutch, usually taken in English sources to have meant "good day", with reference to the revolt of Bruges in 1302, at which the guildsmen of Bruges purportedly took over the city by greeting people in the streets, and murdering anyone who answered with a French accent. This derivation of the name may however be spurious.