- a tube, channel, or canal through which a gas or liquid moves
- a tube in the body for the passage of excretions or secretions: a tear duct, bile duct
- a conducting tubule in plant tissues, esp. one containing resin, latex, etc.
- a pipe or conduit through which wires or cables are run, air is circulated or exhausted, etc.
ML ducta, conduit < L ductus, a leading, conducting, pp. of ducere, to lead < IE base *deuk-, to pull > tow, tug, L dux, leader