What does chock mean?
A chock is a wedge-shaped block, typically made of wood, rubber, or metal, placed firmly against a wheel, barrel, or similar object to stop it from rolling or shifting. Chocks are essential safety equipment in aviation, where ground crews place them under an aircraft's landing gear while parked, and in haulage and shipping, where they stabilise trailers, rail wagons, and cargo. Used as a verb, 'to chock' means to secure something in this way, as when dockworkers chock barrels to keep them steady at sea. The word also lives on in the familiar expression 'chock-a-block', meaning crammed full to capacity, which reflects the idea of packing things so tightly that wedges are needed to hold them in place. Practical, unglamorous, and indispensable, 'chock' is a small word that names one of engineering's simplest and most reliable solutions to a basic problem: stopping things from moving when they shouldn't.
A wedge or block of wood or other material placed against a wheel, barrel, or other object to prevent it from moving or rolling.
"The pilot checked that the wheel chocks had been removed before taxiing."
Most commonly encountered in aviation, maritime, and transport contexts.
To secure or steady an object, especially a vehicle or vessel, by placing a wedge or block against it.
"The crew chocked the wheels before loading the heavy machinery."
Typically used in technical or professional registers rather than everyday speech.
Standard English plural; frequently used in the plural since objects are usually secured at more than one point.
"The ground crew removed the chocks and signalled the captain that the aircraft was clear to push back."
That little block of wood keeping an aeroplane's wheels from rolling has been quietly saving lives for centuries — and it gave us the phrase 'chock-full' along the way.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of chock
The word 'chock' first appears in English in the early 18th century, though its exact origins are uncertain. It is generally thought to derive from the Old French word 'çoche', meaning a notch or nick, which itself may be of Germanic origin. This would connect it to words like 'chuck' and possibly 'shock', suggesting a shared root related to striking or fastening. Its adoption into English coincided with growing maritime and industrial activity, where the need for a specific term for a securing wedge became pressing.
Related word forms
How chock is actually used
The noun sense dominates everyday usage, especially in aviation, shipping, and automotive contexts. The verb form is common in technical and maritime registers but rare in casual speech. The adverbial use survives mainly in the fixed expression 'chock-a-block', meaning completely full.
Easily confused with chock
Chalk is a soft white limestone used for writing or drawing, while a chock is a wedge used to prevent movement.
To chuck means to throw or discard something, whereas to chock means to secure an object with a wedge.