bridge
A transportation structure spanning a gap or water between two points, distinct from connecting parts of buildings.
A bridge is a structure for transportation which connects two points over a gap, chasm, or body of water. Bridges which belong to buildings, such as skybridges and connecting walkways, do not count as separate structures.
Structures used for purposes other than transportation, which happen to span an open gap (such as a house which spans a stream), are not considered bridges, even though their engineering and their shape may be similar. However, a bridge may be lined with enclosed structures that hold usages (like shops and restaurants).
The spanning form serves movement between the two points. Shops or other enclosed uses can accompany that transport function without making the span merely a building over a gap.