Definitions of rachis
  1. noun
    axis of a compound leaf or compound inflorescence
    see moresee less
    type of:
    the main stem or central part about which plant organs or plant parts such as branches are arranged
  2. noun
    the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
    synonyms: back, backbone, spinal column, spine, vertebral column
    see moresee less
    a flexible rodlike structure that forms the supporting axis of the body in the lowest chordates and lowest vertebrates and in embryos of higher vertebrates
    backbone of an animal
    a notochord of a larval tunicate typically confined to the caudal region
    type of:
    skeletal structure
    any structure created by the skeleton of an organism
Word Family

Test prep from the experts

Boost your test score with programs developed by Vocabulary.com’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.


  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week


  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week