glottis vs trachea

glottis

noun
  • The opening between the true vocal cords which is located in the larynx and affects voice modulation through expansion or contraction. 

trachea

noun
  • A thin-walled, cartilaginous tube connecting the larynx to the bronchi. 

  • One of the cuticle-lined primary tubes in the respiratory system of an insect, which extend throughout its body. 

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