transpontine

Usually the prefix trans-, meaning "across," allows for a reciprocal perspective. Whether you're in Europe or America, for example, transoceanic countries are countries across the ocean from where you are. But that's not the way it originally worked with "transpontine." The "pont-" in "transpontine" is from the Latin pons, meaning "bridge," and the bridge in this case was, at first, any bridge that crossed the River Thames in the city of London. "Across the bridge" meant on one side of the river only - the south side. That's where the theaters that featured popular melodramas were located, and Victorian Londoners first used "transpontine" to distinguish them from their more respectable "cispontine" ("situated on the nearer side of a bridge") counterparts north of the Thames.