Definition of femur in US English:



  • 1The bone of the thigh or upper hind limb, articulating at the hip and the knee.

    • ‘Bruising of the articular cartilage of the femur (thigh bone) is also seen on the MRI scans of these patients.’
    • ‘In long bones, such as the femur (thigh bone) a more complex, spiral fracture is more common.’
    • ‘Several areas of the pelvis and the femur are likely to sustain injuries.’
    • ‘Certain fractures of larger long bones, such as the femur, are hard to keep straight in a cast.’
    • ‘Now he has been left hobbling on crutches after muggers fractured the top of his femur (thigh bone) while trying to rip off his running shoes.’
    1. 1.1Zoology The third segment of the leg in insects and some other arthropods, typically the longest and thickest segment.
      • ‘While the femur could likely fold back against the side to a considerable degree, it cannot rotate dorsoventrally.’
      • ‘Many of the diplodocid femora examined were stored, mounted, or damaged in such a way that measurement of their anterior surfaces was difficult or impossible.’
      • ‘Upon thawing, the head and left metathoracic femur of each moth were removed and dried.’
      • ‘Severe injuries, involving the loss of tibiae, femora, and entire legs were rare but did occur in four exclusive and six nonexclusive pairs.’
      • ‘Relative to the foundress, soldiers have an enlarged prothorax and fore femora, reduced wings and antennae, and a pale exoskeleton.’


Late 15th century: from Latin femur, femor- ‘thigh’.