rachis vs spinal column

rachis and spinal column both are nouns.

Word	Noun	Adjective	Verb	Adverb
rachis	Yes	No	No	No
spinal column	Yes	No	No	No

As nouns, rachis and spinal column are synonyms defined as:

rachis and spinal column: the series of vertebrae forming the axis of the skeleton and protecting the spinal cord

Other synonyms of rachis include back, backbone, spine, vertebral column.

rachis (noun)	spinal column (noun)
the series of vertebrae forming the axis of the skeleton and protecting the spinal cord	the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
axis of a compound leaf or compound inflorescence