ward

lock device

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The Information Architects of Encyclopaedia Britannica

Last updated

July 15, 2026

Quick Summary

A ward is a projection inside a lock that prevents a plain key from turning. Keys are designed with slots that correspond to these wards, allowing the key to turn and operate the lock. This system, invented by the Romans, was the primary method of lock security for centuries. While effective, warded locks were susceptible to picking. Modern locks, like the Yale cylinder lock, use pins and tumblers, offering greater security and thousands of variations. The "step ward" is specifically the ward closest to the pin in a lock mechanism.123

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lock
Early history.
The Romans invented wards—i.e., projections around the keyhole, inside the lock, which prevent the key from being rotated unless the flat face of the key (its bit) has slots cut in it in such a fashion that the projections pass through the slots. For centuries locks depended on…
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The Romans invented wards—i.e., projections around the keyhole, inside the lock, which prevent the key from being rotated unless the flat face of the key (its bit) has slots cut in it in such a fashion that the projections pass through the slots. For centuries locks depended on…
Read More