Where is the Autocorrect dictionary file for Outlook 2015 stored in OS X Yosemite?
I believe the autocorrect entries are shared by all Office applications.

Unlike Office 2011 which stores the user's autocorrect items in the ~/Library/Preferences/Microsoft/ folder, Office 2015 Preview seems to use a more obscure location:

~/Library/Group Containers/*.Office/Microsoft Office ACL [English]


Where the * represents a string of characters which may or may not be significant (so I've removed them).