* General: The air conditioning duct was leaking, causing a cold draft in the room.
* Medical: The surgeon carefully repaired the duct that carried bile from the liver.
* Engineering: The engineer designed a system of ducts to efficiently move the hot air away from the furnace.
* Figurative: She had a duct for creativity, constantly coming up with new ideas.
* Idiomatic: He was told to keep his emotions in check, but he couldn't duct his anger any longer. (This is a humorous, informal use, playing on the sound of the word.)