fibula

noun

fib·​u·​la ˈfi-byə-lə 

plural fibulae ˈfi-byə-lē  -lī  or fibulas

1

: the outer and usually smaller of the two bones between the knee and ankle in the hind or lower limbs of vertebrates

2

: a clasp resembling a safety pin used especially by the ancient Greeks and Romans

fibular

ˈfi-byə-lər 

adjective

Illustration of fibula

• fibula 2

Examples of fibula in a Sentence

Recent Examples on the Web

The Giants expect an earlier return from Skattebo, who sustained a dislocated right ankle, a fibula fracture and a deltoid ligament rupture in late October, requiring emergency surgery. —Peter Sblendorio, New York Daily News, 20 Jan. 2026

The tibia and fibula form the socket for the ankle joint, while the talus is the ball. —Parker Gabriel, Denver Post, 19 Jan. 2026

Brown saw his 2024 season cut short with two fractures in his right fibula but was available all year for a team that demands a lot from its tackles. —Paul Dehner Jr, New York Times, 15 Jan. 2026

Morton has battled a hairline fibula fracture for most of the season, spending weeks in a protective boot between games. —Steve Gorten, Miami Herald, 31 Dec. 2025

Word History

Etymology

Latin, pin, clasp; akin to Latin figere to fasten

First Known Use

1578, in the meaning defined at sense 1

Kids Definition

fibula

noun

fib·​u·​la ˈfib-yə-lə 

plural fibulae -ˌlē 

-ˌlī

or fibulas

: the outer and usually the smaller of the two bones between the knee and ankle of the hind or lower limb

fibular

-lər 

adjective

Medical Definition

fibula

noun

fib·​u·​la ˈfib-yə-lə 

plural fibulae

-lē also -ˌlī

or fibulas

: the outer or postaxial and usually the smaller of the two bones of the hind or lower limb below the knee that is the slenderest bone of the human body in proportion to its length, articulates above with the external tuberosity of the tibia and below with the talus, and has its lower end forming the external malleolus of the ankle

called also calf bone

fibular

-lər 

adjective