mulch vs semifluid

mulch

noun
  • Any material used to cover the top layer of soil to protect, insulate, or decorate it, or to discourage weeds or retain moisture. 

verb
  • To apply mulch. 

  • To turn into mulch. 

semifluid

noun
  • Any substance with properties intermediate between those of a solid and a liquid. 

adj
  • Having properties intermediate between liquids and solids 

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