Worm

From WikiPOBia

Worming is a technique to protect line from water damage. Relatively small, generally worn or otherwise cheap line was pressed into the cavities between the strands of a larger line. This worming protected the interior of the larger line, particularly if the worming were adequately tarred, by preventing water from collecting in the cavity or reaching the inner fibers of the strands. Thus, standing rigging was most fully protected by being wormed, parceled, and served.