Included with the Dictionary.app are three plugins (size varies) that you probably don’t need, well, unless you know Japanese:
1. Shogakukan Daijisen.dictionary (44.8MB)
2. Shogakukan Progressive English-Japanese Japanese-English Dictionary.dictionary (66.9MB)
3. Shogakukan Ruigo Reikai Jiten.dictionary (5MB)
Even if one uses a foreign language package remover, these plugins may remain.
It is safe to delete them, but if you are wary, they may moved to a new location in case you need to return them whence they came. Of course, there'll be no savings that way, but you may feel more secure while verifying the safety of my counsel.
Not a big savings, but every 116MB helps…
The location of these plugins is: Computer/Library/Dictionaries
