1 C1 formal
In engineering or manufacturing, to reduce the cross-sectional diameter of a material at a specific point.
"The pipe necks down to 10mm at the joint to fit the smaller coupling."
inseparable
neck down
C1 formal separable transitive/intransitive
Technical term for a shape or component that narrows at a specific point, or in manufacturing, to reduce the diameter of a material.
In plain English
To get narrower in the middle or at one end, like the neck of a bottle.
What does "neck down" mean?
2 meanings, ordered from most common to least. Color-coded by CEFR level.
2 C1 idiomatic formal
To reduce or limit something, such as bandwidth or capacity, at a specific point in a system.
"The network necks down at this node, causing a bottleneck during peak hours."
inseparable
Literal vs figurative
Words literally mean
To shrink like a neck — the shape narrows as a bottle does at its neck.
Actually means
To get narrower in the middle or at one end, like the neck of a bottle.
Usage tip
Primarily used in engineering, manufacturing, and telecommunications contexts. In telecom, 'necking down' can refer to reducing bandwidth. Rarely used outside technical fields.
Words that pair with "neck down"
Natural word combinations native speakers use most often.
bandwidth pipe tube channel diameter
How to conjugate "neck down"
The five tense forms you'll use most often.
Base
neck down
I/you/we/they
3rd person
necks down
he/she/it
Past simple
necked down
yesterday
Past participle
necked down
have + pp
-ing form
necking down
continuous
Hear "neck down" in the wild
Listen to native speakers using "neck down" in real YouTube videos — click a clip to watch it on Looplines.
Other ways to say "neck down"
Swap in when you want variety — tap a linked one to explore it.
constrict narrow reduce in diameter taper
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