Knob (noun)

1. A rounded projection or protuberance, especially one used for grasping.
2. A round handle for turning or opening a door or drawer.

Origin:

Middle english, from old english cnæb; akin to old high german knopf knob.

Examples:

1. I opened the door with a twist of the doorknob.
2. The knobs on the old dresser were made of brass.
3. The chef adjusted the heat on the stove using a knob.
4. The stereo volume was controlled by a large knob.
5. The ancient temple door had a bronze knob shaped like a snake.