radicle

n part of a plant embryo that develops into the main root 幼根; 胚根.

racketeering, rackety, raconteur, racoon, racy, RADA, radar, radar trap (also speed trap), radial, radially, radiance, radiant, radiantly, radiate, radiation, radiation sickness, radiator, radical, radicalism, radically, radii, radio, radio astronomer, radio astronomy, radio car, radio cab, radio frequency, radio telescope, radio transmitter, radio-, radio-astronomer, radio-carbon, radio-controlled, radio-frequency, radio-therapist, radio-therapy, radioactive, radioactivity, radiogram, radiograph, radiographer,