horsetail vs ponytail

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. 

ponytail

noun
  • A hairstyle where the hair is pulled back and tied into a single "tail" which hangs down behind the head. 

verb
  • To form (the hair) into a ponytail. 

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