The geographical term 'promontory' is another word for what?
A promontory is a raised mass of land that projects into a lowland or a body of water (in which case it is a peninsula). Most promontories either are formed from a hard ridge of rock that has resisted the erosive forces that have removed the softer rock to the sides of it, or are the high ground that remains between two river valleys where they form a confluence. A headland, or head, is a type of promontory.
Located at the edge of a landmass, promontories offer a natural defense against enemies, as they are often surrounded by water and difficult to access. Many ancient and modern forts and castles have been built on promontories for this reason.
One of the most famous examples of promontory forts is the Citadel of Namur in Belgium. Located at the confluence of the Meuse and Sambre rivers, the citadel has been a prime fortified location since the 10th century. The surrounding rivers act as a natural moat, making it difficult for enemies to access the fort.
More Info:
en.wikipedia.org