radii

pl of radius.

rackety, raconteur, racoon, racy, RADA, radar, radar trap (also speed trap), radial, radially, radiance, radiant, radiantly, radiate, radiation, radiation sickness, radiator, radical, radicalism, radically, radicle, 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, radiography,