Lock vs Secure

When to use each in English, with meaning, register, and examples.

Lock

Top 1,000 (very common)A2verb

Secure

Top 1,000 (very common)B2verb
 LockSecure
Pronunciation🇬🇧 /["/lɒk/","/lɒks/","/lɒkt/","/ˈlɒkɪŋ/"]/🇺🇸 /["/lɑːk/","/lɑːks/","/lɑːkt/","/ˈlɑːkɪŋ/"]/🇬🇧 /["/sɪˈkjʊə(r)/","/sɪˈkjʊəz/","/sɪˈkjʊəd/","/sɪˈkjʊərɪŋ/"]/🇺🇸 /["/sɪˈkjʊr/","/sɪˈkjʊrz/","/sɪˈkjʊrd/","/sɪˈkjʊrɪŋ/"]/
MeaningA device that keeps things secure and needs a key or combination to open.To make safe or protect something.
ExamplePlease make sure to lock the door before you leave.We need to secure the doors before we leave for the night.
RegisterNeutralNeutral
How commonTop 1,000 (very common)Top 1,000 (very common)
CEFR levelA2B2
Part of speechverbverb
Collocationscarefully, automatically, electronically, forget to, be firmly locked, be securely locked, keep something locked, away, in, in, be safely locked, be securely lockedeasily, safely, eventually, be able to, manage to, fail to, an attempt to secure something, an effort to secure something, be aimed at securing something, firmly, properly, tightly, to, with
Antonymsunlock, opendanger, unsecure, risk
Common mistakesConfused with 'unlock', not realizing they are opposites., Using 'lock' as a noun instead of a verb incorrectly., Mispronouncing 'lock' as 'luck'.Confused with 'ensure' - 'ensure' means to make sure something happens., Using 'secured' as an adjective when it should be a verb., Misplacing the emphasis on the second syllable.
Usage notesUse 'lock' when talking about securing something, like a door or a bike. Avoid using it in very casual conversations where simpler terms like 'close' may be more appropriate.Used to indicate making something safe, but can also mean to obtain or achieve something. More common in formal contexts when referring to safety and in neutral situations for obtaining.

See it in real clips

Lock
Secure

Frequently asked questions: Lock vs Secure

What's the difference between Lock and Secure?

Lock: A device that keeps things secure and needs a key or combination to open. Secure: To make safe or protect something.

Which is more advanced: Lock and Secure?

Secure is the highest level, at B2, on the CEFR scale.

Are Lock and Secure the same CEFR level?

Lock: A2, Secure: B2 on the CEFR scale.

What part of speech are Lock and Secure?

Lock: verb, Secure: verb.

Can you show an example of each?

Lock: Please make sure to lock the door before you leave. Secure: We need to secure the doors before we leave for the night.

Can I use Lock and Secure interchangeably?

Not always. Lock and Secure are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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