The term 'OLD RADIO OR TV PART' can be summarized by the four-letter word 'KNOB'. A KNOB is a round handle or dial used to control the volume, tuning, or other settings on an old radio or television. It is usually made of plastic or metal and is attached to a shaft that turns a potentiometer or switch. Knobs are still used today in many electronic devices, but they are most commonly associated with vintage radios and televisions.