I don't think there is a sharp border when something starts to be dating. Probably it varies widely between different couples.
When 2 persons meet and starts to feel that it might lead to a relationship in the future, I would call it dating. But as you say, it's difficult to know what the other person thinks in the beginning.
But you will probably never find 1 universal definition of dating.
Is this an outing with a woman/man, no matter of what character?
I see 'woman+man' go out only as friends in Poland. So this would not be a good definition of dating.