to make cloth (especially tweed ) denser and more felt-like by soaking and beating.
The frame on which the cloth is waulked is a board some twelve to twenty-four feet long and about two feet broad, grooved lengthwise along its surface.
From Middle English walken, from Old English wealcian (“to roll up; muffle up”), from Proto-West Germanic *walkōn, from Proto-Germanic *walkōną (“to roll about; full (cloth)”).
Cognate with Scots waul...