Actually, I have answered the question of my definition of God in a number of posts, and have pointed to Prudence Louises’ definition as one of the best I have seen. Most simply I would define God as the ground of being.

If you mean by verifiable evidence absolute “proof” of course I can’t do that any more than one can prove God does not exist. That’s the fun of this isn’t it. But I have clearly laid out my reasons for why I believe God exists in my many posts on Medium, most specifically in the 25 or more posts on the the Case Against Physicalism. Also, I think Stephen Meyer has done a solid job of accumulating the evidence for God as creator and designer in his book Return of the God Hypothesis.

Since scientists are seen in our culture as the ultimate sources of knowledge and wisdom on these things, (I suspect you might agree), you might be interested in Cosmos, Bios, Theos which records what many of the best scientists of today and the recent past have said about God, many of them Nobel laureates.