Tibia \Tib"i*a\, n.; pl. {Tibi[ae]}. [L.] 1. (Anat.) The inner, or preaxial, and usually the larger, of the two bones of the leg or hind limb below the knee.
2. (Zo["o]l.) The fourth joint of the leg of an insect. See Illust. under {Coleoptera}, and under {Hexapoda}.
3. (Antiq.) A musical instrument of the flute kind, originally made of the leg bone of an animal.