n. In organ-building, a stop of the open diapason species, with pipes of an exceptionally broad scale, giving a full, powerful tone. Different varieties are known by specific names, as tibia plena, tibia profonda, etc.n. In anatomy and zoology, the inner and usually the larger of the two bones of the crus, or lower leg, extending from the knee to the ankle; the shin-bone of man.n. In ornithology, the tibiotarsus. In some birds, as the loon, the tibia develops an immense apophysis which projects far above the knee-joint. See also cuts under Dromæus and tibiotarsus.n. That segment of the hind limb which extends from the knee to the ankle; the part of the leg corresponding to the extent of the tibia; the crus; the drumstick of a fowl: used especially in ornithology.n. In entomology, the fourth and penultimate joint of the leg, between the femur and the tarsus.n. An ancient variety of flageolet, or direct flute, single or double. See flute, 1 .