As nouns the difference between footbridge and underpass
is that footbridge is a bridge over a road, railway, river, etc for pedestrians while underpass is a road or a pedestrian passage in a tunnel that runs underneath a road or railroad.
footbridge
English
Noun
(
en noun)
A bridge over a road, railway, river, etc for pedestrians.
underpass
English
Noun
(es)
A road or a pedestrian passage in a tunnel that runs underneath a road or railroad.
Synonyms
* subway (UK)
Related terms
* overpass