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Allen key Line breaks: Allen key
Pronunciation: /ˈalənkiː/
(US Allen wrench)

Definition of Allen key in English:


British trademark
A spanner designed to fit into and turn an Allen screw.
Example sentences
  • Presumably it arrived in a flat pack with instructions and an Allen key.
  • However, there are some differences in how the blades are changed, ranging from a hex-head set screw that requires an Allen wrench to a simple flip-lever design that does need a tool.
  • Packing a small adjustable spanner and a set of Allen keys will make sure you can do those last-minute running repairs.


1960s: from the name of the manufacturer, the Allen Manufacturing Company, of Hartford, Connecticut.

Definition of Allen key in:
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