family business; family trade
Refers to a business or trade passed down through generations within a family.
After graduating from university, he took over the family business.
one's occupation; one's trade
A somewhat formal or literary way to refer to one's own profession or trade, often with a nuance of it being a family or inherited calling.
He works as a carpenter by trade.
The eldest son ended up taking over his father's family business.
They have run a sake-brewing family business for generations.
I had been helping with the family business since my student days.
His family's occupation is farming.