Definition of femur in US English:


nounPlural femora, Plural femurs

  • 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.’
    • ‘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.’
    • ‘Several areas of the pelvis and the femur are likely to sustain injuries.’
    • ‘In long bones, such as the femur (thigh bone) a more complex, spiral fracture is more common.’
    1. 1.1Zoology The third segment of the leg in insects and some other arthropods, typically the longest and thickest segment.
      • ‘Upon thawing, the head and left metathoracic femur of each moth were removed and dried.’
      • ‘Relative to the foundress, soldiers have an enlarged prothorax and fore femora, reduced wings and antennae, and a pale exoskeleton.’
      • ‘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.’
      • ‘Severe injuries, involving the loss of tibiae, femora, and entire legs were rare but did occur in four exclusive and six nonexclusive pairs.’
      • ‘While the femur could likely fold back against the side to a considerable degree, it cannot rotate dorsoventrally.’


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