knuckle(redirected from knuckle under)
Also found in: Dictionary, Thesaurus, Medical, Legal, Idioms.
Related to knuckle under: knuckling down
1. a joint of a finger, esp that connecting a finger to the hand
2. the cylindrical portion of a hinge through which the pin passes
3. an angle joint between two members of a structure
The part of a hinge containing the holes through which the pin passes.
The place on an incline where there is a sudden change in grade.
One of the cylindrically projecting parts of a hinge through which the pin passes.