glottis vs larynx

glottis

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

larynx

noun
  • A hollow muscular organ of the neck of mammals situated just below where the tract of the pharynx splits into the trachea and the oesophagus. It is involved in breath control and protection of the trachea, and, because it houses the vocal cords, sound production. 

  • Meronyms: epilarynx, hypolarynx, orolarynx 

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