from where? whence?: a question word asking the origin, source, or cause of something
This is a question word that asks one basic thing: where does this come from? Depending on the situation, that origin can be a physical place a person or thing came out of, a source or means by which something is supplied, or a cause behind an event. All three uses share the same picture of tracing something back to its starting point.
A large group of these questions ask about place, especially about where a person is from. In John's Gospel this becomes a running theme: people keep asking where Jesus is from, and the point is that they think they know his earthly hometown while missing that he comes from the Father. Pilate asks Jesus the same question, and Jesus says he knows where he came from and where he is going.
A second group asks about source or means: from what supply will we get bread in the wilderness, from what source did a man get his wisdom and mighty works, from what cause do fights break out among believers. Here the question is less about a location and more about the means or the origin behind something.
A third, smaller group stretches the same question into an expression of wonder, closer to how can this be? When Elizabeth asks how it is that the mother of her Lord comes to her, or when Jesus asks how David can call his own son Lord, the origin question has become a way of marveling that something is even possible.