rachidian
/rəˈkɪdɪən/(also rhachidian)
adjective
1 Anatomy. Of or relating to the spine; spinal; vertebral.
2 Zoology. In a gastropod mollusc: designating or relating to any of the median row of teeth of the radula.
noun
Zoology. A rachidian tooth of a gastropod mollusc.
Origin
Early 19th century; earliest use found in The Lancet. From French rachidien from scientific Latin rachid- (taken as stem of rachis) + French -ien.