It's not uncommon today for someone to suggest that Christians, Muslims, Atheists and others mean the same thing when they use the word "God".
John Piper offers a really helpful illustration here Response to a common word, where he suggests (around 5 minutes into the video) that it's like two old friends arguing about someone they went to University with 30 years previously. Someone comes up and says, "Why don't you look in the year book"
And they open it up and realise that they weren't talking about the same person.
Jesus is the yearbook. (Does it work if we say facebook?)
Look at Jesus and ask, is that who you mean by God?
And if not then we're talking about a different God.
Which is a great basis for talking, but the conversation proceeds differently than trying to squeeze everyones different ideas into the word "God".
Christians, say God is who you know when you know Jesus.