/spaɪn/·noun·c. 1398 CE, in Trevisa's translation of Bartholomaeus Anglicus 'De Proprietatibus Rerum'·Established
Origin
From Latin spina (thorn, backbone), itself from PIE *spei- (to pierce, be sharp), spine entered English in the late 1300s with its anatomical sense displacing the botanical one — the same root that gave English spike, spire, and French épine (still meaning both thorn and backbone).
Definition
The series of vertebrae extending from the skull to the pelvis that encloses the spinal cord and forms the central axis of the skeleton; also, any sharp, rigid, pointedprojection on a plant or animal.
The Full Story
LatinClassical Latin, with English adoption c. 1400 CEwell-attested
English 'spine' derives from Latin 'spina', meaning 'thorn, prickle, spike' and by extension 'backbone, spine'. The Latin word is well attested in Classical authors: Pliny the Elder uses 'spina' for the thorns of plants, and Celsus (1st century CE) uses it anatomically for the vertebral column. The semantic bridge between 'thorn' and 'backbone' reflects the pointed, projecting nature of vertebral processes — the spinous processes of vertebrae visually resemble thorns or spikes projecting from a central stem. Latin 'spina' derives from Proto-Indo-European *spei- or *sp(h)ei-, a root meaning 'sharp point, spike'. This
Did you know?
In ancient Roman circuses, the long central barrier dividing the track — the island around which chariotsraced at lethal speed — was called the spina. Architects and engineers used the same word for the structural backbone of a building or arch. So when we talk about the spine of a book, we're using a term that passed through vertebral anatomy, plant thorns, and chariot-racing infrastructure before landing on a bookshelf.
'sphya-' (wooden sword or spit), Old English 'spīr' (blade of grass, shoot). By the 16th century English 'spine' was firmly established in anatomical discourse. The metaphorical sense — moral courage ('spineless') — is attested from the 19th century. The publishing sense — the spine of a book — appears from the late 18th century. Key roots: *spei- (Proto-Indo-European: "sharp point; spike; to be sharp or pointed"), spina (Latin: "thorn, prickle; backbone"), espine (Old French: "thorn; spine").