Thanks for the note! So, this one is a little complicated. The short version is that both names are tagged in a way that follows the OSM conventions. Which name is displayed most prominently is a decision made by developer of the specific app or website using OSM data.

The area is broken down into three different boundaries in OSM. I’m also seeing four English names in use to identify parts of the Halifax Citadel areas.

The four names are:
The common “name” used is "Citadel Hill"
The “official name” used is "Halifax Citadel National Historic Site”
The fort itself is "Halifax Citadel"
There is also an "old_name" listed for the fort portion, "Fort George"

The three areas are:
1. The fort itself. So, the ditch and everything within it. This is tagged with the name “Halifax Citadel” and the “old_name” “Fort George”

2. The archaeological site which covers the entire area bordered by Brunswick, Sackville, Bell, Ahern, Rainnie, and Gottigen. This is tagged with the “name” “Citadel Hill” a