het vs thermal

het

adj
  • Heated. 

  • heterozygous 

  • Heterosexual. 

noun
  • A heterosexual person. 

  • Fan fiction based on celebrities or fictional characters involved in an opposite-sex romantic and/or sexual relationship. 

  • heterozygote 

thermal

adj
  • Pertaining to heat or temperature. 

  • Caused or brought about by heat. 

  • Having a rough finish by treatment with a blow-torch. 

  • Providing efficient insulation so as to keep the body warm. 

noun
  • A column of rising air in the lower atmosphere created by uneven heating of Earth's surface. 

verb
  • To create a rough finish on stone by treating it with a high-temperature blow-torch. 

  • To fly an unpowered aircraft in a (thermal) column of rising air. 

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