a screw turned by means of an axial hexagonal hole in its head.
- Allen test
allen test Allen test n. A test for occlusion of the radial or ulnar artery, in which one of these arteries is compressed after blood has been forced out of the hand by clenching it into a fist; failure of the blood to diffuse into the hand when opened indicates that the artery not compressed […]
- Allen wrench
a wrench for Allen screws, formed from a piece of hexagonal bar stock bent to a right angle. noun See Allen key
- Allen’s law
allen’s law Allen’s law Al·len’s law (āl’ənz) n. The principle that, in contrast to a normal physiology, the more carbohydrate taken by a diabetic, the less carbohydrate is utilized.
- Allen’s rule
allen’s rule Allen’s rule (āl’ənz) The principle holding that in a warm-blooded animal species having distinct geographic populations, the limbs, ears, and other appendages of the animals living in cold climates tend to be shorter than in animals of the same species living in warm climates. Shorter and more compact body parts have less surface […]