A part that protrudes or extends outward
An unevenness or elevation on a surface
She turned the knob, but the door didn't open.
He was a stout, dark, red- faced peasant in the forties, with thick lips, a broad knob of a nose, similar knobs over his black frowning brows, and a round belly.
She turned the porcelain knob and pushed the door open.
When she'd finished, she twisted the knob and pulled.
At the door he paused with his hand on the knob, his tone once again authoritative.