1. a rounded handle or control device that you turn or pull
2. a rounded lump or swelling on a surface
3. a small rounded hill

1. to hit or strike something
Usage: informal

Examples

• Turn the knob to adjust the volume.
• The door knob was made of brass.
• There’s a small knob on the tree trunk where a branch was cut.
• The old oak had several knobs along its bark.
• They climbed to the top of the grassy knob.
• He accidentally knobbed his head on the low beam.
• The radio knob broke off in my hand.