What does the yiddish term kinder mean?

In the days before internet, and when international phone calls were rare and expensive, children who grew-up and left the house to live in a far away place were referred to as 'paper children', because the only way to communicate with them was through the letters they sent you. Perhaps there was also a hint of dissatisfaction with the fact that they didn't make the effort to travel and see their parents from time to time....