Final answer:
The broad, slightly dome-shaped landform with a low slope over a large area described in your question is known as a plateau, which is elevated and larger than a mesa. The Interior Lowlands around Hudson Bay is an example of such a plateau.
Step-by-step explanation:
The subject of your question relates to a broad, slightly dome-shaped landform with a low slope that extends over a large geographic area. This description best matches that of a plateau, which is a large flat area that covers a large region and is elevated above its surroundings. A plateau is more extensive than a mesa and is a common geographical feature found in various parts of the world.
One example of a geographical region that fits this definition is the Interior Lowlands around Hudson Bay, which is a flat, rocky region covering nearly two million square miles. This area consists largely of Paleozoic marine rocks like limestones and shales shaped by glacial and river activities.
In addition to the above, a dome can refer to a hemispherical interior space in architecture, known simply as a dome, formed by various construction methods, including corbelling. The term 'dome' in geography may also refer to a landform with a distinct shape, but it is different from the slightly dome-shaped plateau described in the initial query.