In building and DIY terms, ‘conduit’ refers to either a tube which covers and protects electrical wires or cables, or a tube for transporting gases, liquids or other substances which can flow. Conduits can be made from various metals, plastics or rubbers. They also come in many sizes and are used for different applications such as electrical fitting, plumbing and in motors.
Generally, when tubes or pipes are mentioned, it is a reference to a cylindrical or square tube which has quite a rigid structure and will hold its shape. Hose, or hose pipe, is usually used when referring to tubing that is flexible.
Flexible hose is often used in places where there may be vibrations or stresses that mean the structure needs to be able to move, such as on motors.