I was a fan of the package Dictionaries
but is seems that it is no available and that will not be re-included. The package’s page in package control is here, indicating that the package was removed.
Anyway, the package is in GitHub and it can be installed from the repository. The steps follows:
Downloads
folderunzip Dictionaries-master.zip
mv Dictionaries-master Dictionaries
mv Dictionaries ~/.config/sublime-text-3/Packages
The steps described here are also in the package’s repository (at the end).