cotton wool vs twill

cotton wool

noun
  • Raw fibers of cotton before being processed. 

  • Soft, absorbent cotton for medical or cosmetic use, protective padding, etc. 

twill

noun
  • A cloth or portion of cloth woven in such a pattern. 

  • A pattern, characterised by diagonal ridges, created by the regular interlacing of threads of the warp and weft during weaving. 

verb
  • To weave (cloth, etc.) so as to produce the appearance of diagonal lines or ribs on the surface. 

How often have the words cotton wool and twill occurred in a corpus of books? (source: Google Ngram Viewer )