1 C1 neutral
To secure a bolt, nut, or fitting firmly by tightening it so it cannot move.
"Make sure you tighten down every bolt before you take the engine out for a test run."
separable
tighten down
C1 neutral separable transitive
To fasten or secure something firmly by turning or pressing it downward.
In plain English
To screw or press something tightly so it doesn't move.
What does "tighten down" mean?
2 meanings, ordered from most common to least. Color-coded by CEFR level.
2 C1 idiomatic neutral
To make security or rules stricter in order to prevent problems (less common variant of 'tighten up').
"Management decided to tighten down procedures after the safety audit."
separable
Literal vs figurative
Words literally mean
To make tight by pressing or turning in a downward direction.
Actually means
To screw or press something tightly so it doesn't move.
Usage tip
Primarily used in mechanical and technical contexts. Less common than 'tighten up' and often interchangeable with it in physical senses. More frequent in American English technical manuals.
Words that pair with "tighten down"
Natural word combinations native speakers use most often.
bolt nut screw fitting lid clamp
How to conjugate "tighten down"
The five tense forms you'll use most often.
Base
tighten down
I/you/we/they
3rd person
tightens down
he/she/it
Past simple
tightened down
yesterday
Past participle
tightened down
have + pp
-ing form
tightening down
continuous
Hear "tighten down" in the wild
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