door-knocker

n = knocker.

donate, donation, done, donjon, donkey, donkey engine, donkey jacket, donkey-work, donnish, donor, doodle, doom, doomed, doomsday, door, door-bell, door-frame, door-handle, door-keeper, door-knob, door-plate, door-way, doorbell, doorknob, doorman, doormat, doornail, doorpost, doorstep, doorstop, doorway, dope, dopey (also dopy), Doric, dorm, dormancy, dormant, dormer, dormitory, dormitory town,