dreadlocks vs horsetail

dreadlocks

noun
  • A hairstyle worn by Rastafarians and others in which the hair is left to grow into long matted strings. 

horsetail

noun
  • A ponytail hairstyle. 

  • Any of various simple vascular plants, of the order Equisetales, that have hollow stems and produce spores. 

  • The tail of a horse. 

  • cauda equina, a bundle of nerve fibers. 

  • A Turkish standard denoting rank. 

  • A mare's tail, a water plant in genus Hippuris. 

  • Any waterfall, the descending water of which maintains contact with bedrock most of the time. 

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