femur

American  

[fee-mer] / ˈfi mər /

noun

plural

femurs, femora

1. Anatomy. a bone in the human leg extending from the pelvis to the knee, that is the longest, largest, and strongest in the body; thighbone.

2. Zoology. a corresponding bone of the leg or hind limb of an animal.

3. Entomology. the third segment of the leg of an insect (counting from the base), situated between the trochanter and the tibia.

---

femur British  

/ ˈfiːmə /

noun

1. Nontechnical name: thighbone.  the longest thickest bone of the human skeleton, articulating with the pelvis above and the knee below

2. the corresponding bone in other vertebrates

3. the segment of an insect's leg nearest to the body

---

femur Scientific  

/ fē′mər /

1. The long bone of the thigh or of the upper portion of the hind leg.

2. See more at skeleton

---

Etymology

Origin of femur

1555–65; < Latin: thigh

Example Sentences

Far out in the desert, the researchers gaped at the six-foot-long femur, the jaw, teeth, and base of the crest.

From Barron's • Feb. 27, 2026

Evidence includes a hominin femur marked by clear signs of gnawing.

From Science Daily • Feb. 7, 2026

The ACL, which connects the shin bone to the femur, is a main stabilizing force in the knee and protects the lower leg from sliding forward.

From Los Angeles Times • Feb. 7, 2026

A small section of hip was left of the torso, and there was enough bone in the femur and the hip for pathologists to match them together, confirming it was the same individual.

From BBC • Jan. 31, 2026

Twelve years ago, he was a professional hockey player better known as the Slammer, until he shattered his femur against another player’s head.

From "All The Bright Places" by Jennifer Niven

Related Words

• groin