The Royal Naval Division was a naval infantry force formed during the First World War. It was made up largely of naval reservists, but also included soldiers and marines. While there are not many direct synonyms for the term "Royal Naval Division," there are related terms that can be used to describe it. These include naval infantry, marine brigade, seaborne troops, and amphibious unit. Each of these terms describes the combination of naval and land-based forces that made up the Royal Naval Division, and can be used interchangeably with the original term. Overall, the Royal Naval Division played an important role in the First World War, and its legacy continues to be recognized today.