synthetics vs twill

synthetics

twill

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

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

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

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