means A small, crisp root vegetable, usually red-skinned and white inside, with a sharp peppery taste, eaten raw in salads.

from From Latin 'radix,' meaning 'root' — the same source that gives us 'radical' and 'eradicate,' since to eradicate is literally to tear something up by the roots. The word came into Old English as 'rædic,' borrowed early enough that this peppery little root has been on English tables under a near-identical name for over a thousand years.