What does Boxing Day have to do with boxing?
c.1400, "living and growing as a plant," from Old French vegetable "living, fit to live," from Medieval Latin vegetabilis "growing, flourishing," from Late Latin vegetabilis "animating, enlivening," from Latin vegetare "to enliven," from vegetus "vigorous, active," from vegere "to be alive, active, to quicken," from PIE *weg- "be strong, lively," related to watch (v.), vigor, velocity, and possibly witch (see vigil). The meaning "resembling that of a vegetable, dull, uneventful" is attested from 1854 (see vegetable (n.)).
mid-15c., originally any plant, from vegetable (adj.); specific sense of "plant cultivated for food, edible herb or root" is first recorded 1767. Meaning "person who leads a monotonous life" is recorded from 1921.
Slang shortening veggie first recorded 1955. The Old English word was wyrt (see wort). The commonest source of words for vegetables in Indo-European languages are derivatives of words for "green" or "growing" (cf. Italian, Spanish verdura, Irish glasraidh, Danish grøntsager). For a different association, cf. Greek lakhana, related to lakhaino "to dig."
vegetable veg·e·ta·ble (věj'tə-bəl, věj'ĭ-tə-)
A plant cultivated for an edible part, such as the root of the beet, the leaf of spinach, or the flower buds of broccoli or cauliflower.
The edible part of such a plant.