A funnel is a pipe with a wide, often conical mouth and a narrow stem. It is used to channel liquid or fine-grained substances into containers with a small opening. Without a funnel,spillage would occur.

Funnels are usually made of stainless steel, glass, or plastic. The material used in its construction should be sturdy enough to withstand the weight of the substance being transferred, and it should not react with the substance. For this reason, stainless steel or glass are useful in

transferring diesel, while plastic funnels are useful in the kitchen. Sometimes disposable paper funnels are used in cases where it would be difficult to adequately clean the funnel afterwards (for example, in adding motor oil to a car). Dropper funnels, also called dropping funnels or tap funnels, have a tap to allow the controlled release of a liquid.

The term "funnel" is sometimes used to refer to the chimney or smokestack on a steam locomotive and usually used in referring to the same on a ship. There is also a type of spider known as a funnel-web due to its habit of building its web in the shape of a funnel. The term "funnel" is even applied to other seemingly strange objects like a smoking pipe or even a humble kitchen bin.