Synonyms for Quadruple (same or very similar meaning)
WordNet sense 1 (a set of four similar things considered as a unit):
quadruplet, quartet, quartette
WordNet sense 2 (having four units or components):
fourfold, quadruplicate, quadruplex
WordNet sense 3 (having or involving or consisting of more than one part or entity or individual):
multiple
From the ODE community, based on WordNet
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