What is the meaning of Siding?

A building material which covers and protects the sides of a house or other building.

present participle and gerund of side

A second, relatively short length of track just to the side of a railroad track, joined to the main track by switches at one or both ends, used either for loading or unloading freight, storing trains or other rail vehicles; or to allow two trains on a same track to meet (opposite directions) or pass (same direction) .

mole

Source: wiktionary.org