Rachis
/ˈreɪ.kɪs/noun
The main central axis of a feather, leaf, or compound structure; in anatomy, the spine or spinal column.
Did you know?In Greek, ῥάχις (rhakhis) meant both the back/spine and the central ridge of a plant or feather, which is why the word still feels like a structural “axis” of life.
Etymological Timeline
Proto-Indo-European
PIE
*regʰ-
“to move in a straight line; to stretch or extend”
Ancient Greek
Greek
ῥάχις (rhakhis)
“the spine, back, or ridge; the central axis of something”
Late Latin
Latin
rachis
“spine; central stem or axis”
16th Century
English
rachis
“the spine or the central axis of a feather or plant”
Modern English
English
rachis
“the central supporting axis of a feather, leaf, or similar structure; the spinal column in anatomy”