crevasse vs ostium

crevasse

noun
  • A breach in a canal or river bank. 

  • A discontinuity or “gap” between the accounted variables and an observed outcome. 

  • A crack or fissure in a glacier or snowfield; a chasm. 

  • Any cleft or fissure. 

verb
  • To fissure with crevasses. 

  • To form crevasses. 

ostium

noun
  • The mouth of a river. 

  • A small opening or orifice, as in a body organ or passage. 

  • Any of the small openings or pores in a sponge. 

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