"He walked across the bridge" means he walked entire length of the bridge from one end to other end.
How do I describe the movement width-wise of bridge just like we used the word across for describing the movement length wise.
"He walked across the bridge" means he walked entire length of the bridge from one end to other end.
How do I describe the movement width-wise of bridge just like we used the word across for describing the movement length wise.
Context would normally be sufficient.
Now one day Pooh and Piglet and Rabbit and Roo were all playing Poohsticks together. They had dropped their sticks in when Rabbit said "Go!" and then they had hurried across to the other side of the bridge, and now they were all leaning over the edge, waiting to see whose stick would come out first. But it was a long time coming, because the river was very lazy that day, and hardly seemed to mind if it didn't ever get there at all. (The House at Pooh Corner, IN WHICH Pooh Invents a New Game and Eeyore Joins In.)
No doubt here what "the other side", means.
He crisscrossed across the bridge.
The phrase opposite parapet as commented is good. ResearchGate has this diagram.
He crossed over to the opposite parapet.
Simple terms to describe crossing the width of a bridge:
OP's Query:
"He walked across the bridge".
means he walked the entire length of the bridge, from one end to the other.
"He crossed the bridge on foot".
also conveys the same meaning.
However,
"He walked across the road at the zebra crossing".
means he moved from one side of the road to the other (not from one end to the other).
If you want to describe movement across the width of the bridge (side to side) rather than its length (end to end), you could say:
English doesn't have a single, commonly used word equivalent to "across" for this specific side-to-side context, so phrasing often depends on clarity and context.