What does "knocking" mean?

1. (sound on a door) the sound made when someone hits a door or a hard surface with their hand. 2. (engine noise) a repetitive metallic sound from an engine that is not working correctly.

How do you use "knocking"?

Often used as an uncountable noun when referring to the mechanical phenomenon.

knocking

US //ˈnɑkɪŋ// UK //nˈɒkɪŋ// knock·ing

1 sound on a door (n.)
A2 Elementary

the sound made when someone hits a door or a hard surface with their hand.

the percussive sound produced by striking a surface, typically a door, to attract attention.

Example

I heard a loud knocking at the front door late last night.

Example

The persistent knocking at the gate eventually roused the porter, who had fallen asleep during his midnight shift.
- silence
2 engine noise (n.)
C1 Advanced Technical Science

a repetitive metallic sound from an engine that is not working correctly.

a rhythmic metallic sound in an internal combustion engine, often indicating pre-ignition or mechanical wear.

Example

The mechanic said the knocking in the engine was caused by bad fuel.

Example

The driver noticed a distinct knocking coming from the cylinder head whenever the vehicle attempted to accelerate up a steep incline.

Usage

Often used as an uncountable noun when referring to the mechanical phenomenon.
- pinging
- rattle

Idioms2 entries