Bond energies can be described as either: Formation Energies (exothermic processes) Energy is released to form a bond Dissociation Energies (endothermic processes Energy is consumed to break a bond
Bond energies are determined by the their formation or the dissociation. Exothermic describes energy being released, this is done during a formation of a bond. Endothermic describes energy being "Absorbed", this is done during the breaking of a bond.