baths vs spa

baths

noun
  • A building containing a public swimming pool or shower facilities; originally a place having individual cubicles where people without bathrooms could have a bath. 

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 

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