This excerpt of the error message is quite clear:
In function `Dictionary::Dictionary()':
Dictionary.cpp: multiple definition of `Dictionary::Dictionary()'
main.cpp: first defined here
You are defining the constructor of the Dictionary class twice – once in Dictionary.cpp and then again in Main.cpp. It is almost as if you are defining the constructor in the header file but outside the class definition – you should have any function that is part of the class defined inside the class OR outside the class in ONE cpp source file. You would need to edit your question with all the source code to be sure.
solved c++ objected oriented dictionary program [closed]