grout vs mucilage

grout

noun
  • A thin mortar used to fill the gaps between tiles and cavities in masonry. 

verb
  • To insert mortar between tiles. 

  • To affix with mortar. 

mucilage

noun
  • A thick gluey substance (gum) produced by many plants and some microorganisms. 

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