entry
rachis
/ˈreɪkɪs/Spine, feather shaft, or biological central axis
From Greek rachis (Spine).
from New Latin rhachis/rachis
Word Ancestry
from New Latin rhachis/rachis
Picture a feather held up to the light: the stiff line running through its center is a rachis, a tiny architectural spine. The word comes from Ancient Greek ῥάχις, meaning “spine” or “ridge,” and New Latin carried it into the vocabulary of anatomy and biology. In the Hippocratic medical tradition, the Greek word belonged to the language of the human backbone; later scientists stretched it—quite sensibly—to the shaft of a feather and the main axis of a sea creature. That same image of a raised central ridge explains why botanists use rachis for the axis supporting a compound leaf. So rachis is a compact Greek metaphor: wherever nature builds a structure around a central stiff line, it has made a kind of spine.
The Story
Picture a feather held up to the light: the stiff line running through its center is a rachis, a tiny architectural spine. The word comes from Ancient Greek ῥάχις, meaning “spine” or “ridge,” and New Latin carried it into the vocabulary of anatomy and biology. In the Hippocratic medical tradition, the Greek word belonged to the language of the human backbone; later scientists stretched it—quite sensibly—to the shaft of a feather and the main axis of a sea creature. That same image of a raised central ridge explains why botanists use rachis for the axis supporting a compound leaf. So rachis is a compact Greek metaphor: wherever nature builds a structure around a central stiff line, it has made a kind of spine.
Kin & Kindred
From 'rachis'·Spine, ridge, or raised central axis
Derived Terms
English words from this root