thalamus vs undercroft

thalamus

noun
  • An inner room or nuptial chamber. 

  • The receptacle of a flower; a torus. 

  • A thallus. 

  • Either of two large, ovoid structures of grey matter within the forebrain that relay sensory impulses to the cerebral cortex. 

undercroft

noun
  • A cellar or vaulted storage room. 

  • A ground-level car park that occupies the base of a building. 

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