to hear something from someone who heard it from someone else.
I heard through the grapevine that she likes him.
' But most of me mad dad's crew took off to American from what I can make out' - he's talking too much, he has to stop - 'from what I hear on the family grapevine, that's where they went, New York, their loss as far as I'm concerned, don't know what they're missing, eh? '.