noun: the yarn woven across the warp yarn in weaving
See Wikipedia, Warp and Woof
"And it is thus that, on the ruins of former doctrines and after a century of persistent efforts, there sprang up two sovereign powers which seemed eternal - matter as the fundamental woof of things, and energy to animate it." [THE THEORY OF INTRA-ATOMIC ENERGY AND THE PASSING-AWAY OF MATTER. page 17]
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