the.com/knock
the universal password to a door that has no idea who you are
means To strike a surface with a sharp blow, often to make noise or signal one's presence, or the sound such a blow produces.
from From Old English 'cnocian,' meaning to strike or pound — an echoic word, born from the very sound it names, the dull thud of fist on wood. It has cousins across the old Germanic tongues (Old Norse 'knoka' among them), all of them basically the mouth imitating the hand.
- shave and a haircut
- the two-knock rhythm answered with two beats
- engine trouble
- premature fuel ignition is literally called engine knock
- superstition
- knocking wood to ward off jinxes predates Christianity
- morse cousin
- prisoners tapped grid codes through cell walls to talk
- opportunity
- the proverb says it knocks exactly once
knock on wood — superstition practiced across cultures to ward off bad luck by tapping wood
knock knock jokes — children's joke format popular since 1930s with 'knock knock, who's there' setup
engine knock — combustion phenomenon in cars that damages engines, occurs when fuel ignites prematurely