spa vs sulfur spring

spa

noun
  • A health resort near a mineral spring or hot spring. 

  • A trendy or fashionable resort. 

  • A convenience store. 

  • A health club. 

  • A hot tub. 

  • A clumsy person (see spastic) 

  • An idiot; a gobshite 

sulfur spring

noun
  • a spring of naturally sulfurous water, often of volcanic origin and therefore hot 

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