hogback vs plica

hogback

noun
  • A Viking grave marker taking the form of a recumbent monument, generally with a curved (hogbacked) ridge and outwardly curved sides. 

  • A sharp steep-sided ridge formed by the erosion of tilting strata 

  • A hogframe. 

plica

noun
  • A neume, in the form of a tail at the end of a ligature, indicating an additional note. 

  • Polish plait, plica polonica, or plica neuropatica: a disease of the hair in which it becomes twisted and matted together. 

  • A diseased state in plants in which there is an excessive development of small entangled twigs, instead of ordinary branches. 

  • A fold or crease, especially of skin or other tissue. 

  • The bend of the wing of a bird. 

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