1. In or at the rear of; to the back of; behind.
The garage is hack of the house.
Our car was in hack of theirs at the traffic light.
Being a cause or reason for; causing.
Hard work was back of his success.
The principal tried to find out what was back of the trouble on the bus.
In support or encouragement of; helping, clones will be elected because many powerful men are back of him.
Get in back of your team by cheering them at the game.