We are working on a multilingual dictionary app that takes definitions from various dictionaries online and presents them to the user. I won't get into the specific details about what this app does it differently than others. The innovative part of the dictionary is its user interface. We believe it is going to be extremely useful to a lot of people. The languages include English to English (as in oxford or cambridge dictionary) as well as English to German, German to English.
The problem is that our app will either scrape the definitions from online dictionaries' website (via regex or DOM/xpath/xquery) or receive the definitions from an API and store the definitions. So, the definitions of the terms/word won't be ours. We can "maybe" call them "stolen". What kind of copyright issues if:
1.) we make the project open source and publish it?
2.) we sell it as an app?