# knocking

/ˈnɑkɪŋ/ (US) · /nˈɒkɪŋ/ (UK)

Source: https://englishreference.com/word/knocking
Updated: 2026-06-20

## Senses

### 1. sound on a door

noun · CEFR A2

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

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

- I heard a loud knocking at the front door late last night.
- The persistent knocking at the gate eventually roused the porter, who had fallen asleep during his midnight shift.

### 2. engine noise

noun · CEFR C1 · Technical

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

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

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

## Examples

- I heard a loud knocking at the front door.
- The sudden knocking on the window startled everyone in the living room during the storm.
- A persistent knocking from the engine suggested that the vehicle required immediate mechanical attention before the long journey began.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.