labium vs vagina

labium

noun
  • A liplike part of various invertebrates. 

  • The lip of a labiate corolla. 

  • A liplike structure; especially one of the two pairs of folds of skin on either side of the vulva. 

  • The lip against which pressured air is driven to produce sound in a recorder and in a pipe organ with flue pipes. 

  • A lower mouthpart of an insect that is formed by the second pair of maxillae united in the middle line. 

vagina

noun
  • A similar part in some invertebrates. 

  • The vulva, or the vulva and the vaginal passage collectively. 

  • A sheathlike structure, such as the leaf of a grass that surrounds a stem. 

  • The passage leading from the opening of the vulva to the cervix of the uterus for copulation and childbirth in female mammals. 

  • A coward; a weakling; a pussy. 

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