The term 'DUCT, FOR INSTANCE' is a 10-letter crossword solution that refers to a type of PASSAGEWAY. A duct is a tube or conduit used to transport air, liquids, or other materials from one place to another. Ducts are commonly found in buildings and are used to carry air from heating and cooling systems to different rooms. They can also be used to transport water, gas, and other materials. Ducts are an important part of many different types of infrastructure, and they are essential for the efficient functioning of many systems.