“As late as 1920, Marcel Duchamp said he didn’t know what Dada was. The accounts of the original participants in Zurich are conflicting; there is even uncertainty about where the name came from. The most plausible version is that Ball and Huelsenbeck found the French word for ‘hobbyhorse’ accidentally in a French–German dictionary while looking for something else. Another possibility is that it came from the name of a popular hair-strengthening tonic. Whatever its origin, the word, which in several Slavic languages sounds like an emphatic declaration of agreement (“yes, yes”), quickly became as popular as a brand name: a one-word manifesto guaranteed either to amuse or to irritate.”