Origin and history of *ed-

common name in North America for "lucerne," a plant in the legume family important as a forage crop, 1845, from Spanish alfalfa, earlier alfalfez, said by Iberian sources to be from Arabic al-fisfisa "fresh fodder." Watkins says it is ultimately from an Old Iranian compound *aspa-sti- "alfalfa, clover," from *aspa- "horse" (from PIE root *ekwo- "horse") + -sti- "food," from suffixed form of PIE root *ed- "to eat."

"having power to relieve pain," 1540s, from Medieval Latin anodynus "pain-removing, allaying pain," from Latin anodynus "painless," from Greek anodynos "free from pain," from an- "without" (see an- (1)) + odynē "pain, torment" (of the body or mind), a word of uncertain origin, evidently Indo-European, but none of the proposed etymologies satisfies Beekes. Some suggest it is a suffixed form of PIE root *ed- "to eat" (compare Lithuanian ėdžioti "to devour, bite," ėdžiotis "to suffer pain").

As a noun, "substance which alleviates pain," 1540s; in old slang, frequently a euphemism for "death" (as the final relief from the mental pain or distress of life) as in anodyne necklace "hangman's noose." Related: Anodynous.