"the primitive backbone," 1848, coined in English by English anatomist Sir Richard Owen from chord (n.2) + Greek nōton "back," which is perhaps from the same PIE source as Latin natis "buttock," which is the source of Italian and Spanish nalga, Old French nache "buttock, butt." Related: Notochordal.
1530s, "to poke with a stick," of uncertain origin; possibly [Barnhart, Century Dictionary] a variant of brod, from Middle English brodden "to goad," from Old Norse broddr "shaft, spike" (see brad), or perhaps imitative [OED]. Compare dialectal prog "pointed instrument for poking" (1610s), also as a verb, "to poke about."
Figurative sense of "mental incitement or instigation" is by 1871. Related: Prodded; prodding.
zodiacal constellation usually identified as "the Ram," late Old English, from Latin aries "ram" (related to arietare "to butt"), from a PIE root meaning "spring, jump" (source also of Lithuanian ėrytis, Old Church Slavonic jarici, Armenian oroj "lamb;" Greek eriphos, Old Irish heirp"kid").
The meaning "person born under the sign of Aries" is from 1894; they also have been called Arians (1917).
c. 1400, "of or like a ray or radius," from Medieval Latin radialis, from Latin radius "shaft, rod; spoke of a wheel; beam of light" (see radius). Meaning "arranged like the radii of a circle" is by 1750. As a noun, "a radiating or radial part," by 1872. As a type of tire, attested from 1965, short for radial-ply (tire), so called because the cords run at right angles to the circumference. Related: Radially.
"weapon with a penetrating head and a long wooden shaft, meant to be thrust or thrown," Old English spere "spear, javelin, lance," from Proto-Germanic *sperō (source also of Old Norse spjör, Old Saxon, Old Frisian sper, Dutch speer, Old High German sper, German Speer "spear"), from PIE root *sper- (1) "spear, pole" (source also of Old Norse sparri "spar, rafter," and perhaps also Latin sparus "hunting spear").