1 B1 idiomatic neutral
To secure a fixed price, rate, or agreement that cannot be changed later.
"You should lock in that mortgage rate before it goes up again."
separable
lock in
B1 neutral separable transitive
To secure a rate, agreement, or person in a fixed position, removing the possibility of change, or to confine someone inside a locked space.
In plain English
To fix something firmly so it cannot be changed, or to trap someone inside a locked place.
What does "lock in" mean?
3 meanings, ordered from most common to least. Color-coded by CEFR level.
2 B1 neutral
To confine someone in a locked space so they cannot leave.
"He accidentally locked himself in the shed and had to wait an hour to be let out."
separable
3 B2 idiomatic neutral
To commit a customer or partner to a long-term contract or relationship, making it difficult to leave.
"The subscription service was designed to lock users in through penalty fees for early cancellation."
separable
Literal vs figurative
Words literally mean
To lock someone or something inside so they cannot leave — 'in' implies containment and fixedness.
Actually means
To fix something firmly so it cannot be changed, or to trap someone inside a locked place.
Usage tip
Very common in finance (locking in an interest rate), business (locking in a customer), and sports commentary (locking in a position). The physical sense (trapping someone) is less common.
Words that pair with "lock in"
Natural word combinations native speakers use most often.
rate price deal customer position savings
How to conjugate "lock in"
The five tense forms you'll use most often.
Base
lock in
I/you/we/they
3rd person
locks in
he/she/it
Past simple
locked in
yesterday
Past participle
locked in
have + pp
-ing form
locking in
continuous
Hear "lock in" in the wild
Listen to native speakers using "lock in" in real YouTube videos — click a clip to watch it on Looplines.
Other ways to say "lock in"
Swap in when you want variety — tap a linked one to explore it.
commit to confirm fix guarantee seal secure
Keep exploring
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