Know why cattywampus was trending last week?
1560s, from Latin femur "thigh," of unknown origin; borrowed first as an architectural term, 1799 as "thighbone."
femur fe·mur (fē'mər)
n. pl. fe·murs or fem·o·ra (fěm'ər-ə)
The long bone of the thigh, and the longest and strongest bone in the human body, situated between the pelvis and the knee and articulating with the hipbone and with the tibia and patella. Also called thighbone.
The long bone of the thigh or of the upper portion of the hind leg. See more at skeleton.