Main Entry: tract

Pronunciation: \ˈtrakt\

Function: noun

1 : a system of body parts or organs that act together to perform some function <the digestive tract>—see gastrointestinal tract, lower respiratory tract, upper respiratory tract
2 : a bundle of nerve fibers having a common origin, termination, and function and especially one within the spinal cord or brain—called also fiber tract; see corticospinal tract, olfactory tract, optic tract, spinothalamic tract; compare fasciculus b