Forsake something in negotiations. ‘Ground’ is used as to what someone wanted, but is now giving up a little in order to reach a broader agreement. Typically, used in reference to bargaining wherein one side of a negotiation will give ground in order to achieve a desired end result. Reference to ‘ground’ comes from major armed battles which are often over control of land(ground).

“My parents said I can NOT have a car, but they did give ground and allow me to buy a motorcycle.”