Q: my dictionary crashes intermittently after upgrading to macOS Sierra.

I have the same problem! Since I upgraded to Sierra, Dictionary.app crashes constantly. I searched the net but haven't found a solution. In fact, this page is the first mention I have found that mentions the problem. It's annoying because I use the app many times every day in my work.

Try deleting these two files from your Library/Preferences folder and reboot:

com.apple.DictionaryServices.plist

com.apple.InputMethodKit.UserDictionary.plist

nothing will help with dictionary. I checked with my friends and all have the same problem, dictionary is missing. but they are not posting cus they never used it. I think there is a bug and apple should make updates.