rachis meaning (obsolete): definition, etymology and quotations

rachis

noun

UK, US /ˈɹeɪkɪs/

Etymology From New Latin rhachis/rachis, from Ancient Greek ῥάχις (rhákhis, “spine, ridge”).

Anatomy, Biology, Medicine, Natural sciences, Sciences, Zoology Obsolete The spinal column, or the vertebrae of the spine.

Biology, Natural sciences, Zoology An anatomical shaft or axis in a marine invertebrate.

In some squid species, the pen rachis flares out into wings on either side, and the tip of the rachis grows into a thick cone.2017, Danna Staaf, Squid Empire, ForeEdge, →ISBN, page 115:

Biology, Natural sciences, Ornithology The central shaft of a feather.

Biology, Botany, Natural sciences The axis of either a compound leaf, inflorescence, or fern frond.