Hi,
Both words have a variety of meaning, as I am sure you have already found in your dictionary.
Let me add a few comments, based on the kind of context I think you are thinking about, which is where someone is trying to explain or interpret something to someone else.
Tom gave an explanation of what had happened. Tom made the events clear and understandable.It also often tends to suggest that he did it in a reasonably objective way. Scientists usually say thet are searching for explanations.
Tom gave an interpretation of what had happened. Tom made the events clear and understandable in a way that his audience could understand. For example, if his audience consisted of children, he would explain in terms and images that children could understand. If his audience were priests, he would relate what happened to their religious outlook. That's why, as a simple example, we call someone who translates fron English to Chinese on behalf of other people an interpreter.
Usually and in general terms, an interpretation is seen as more subjective than an explanation.
There are, as I mentioned, other meanings, but consider these to start with.
Best wishes, Clive