A metallic cord for the reinforcement of elastomers has a 4+3 construction wherein the diameter of each filament ranges from 0.35 to 0.50 mm. The lay length of the four filaments in the core may be infinity. A pneumatic tire has a belt structure of at least two radially overlapped layers of elastomeric materials reinforced with metallic cords, each metallic cord of at least one of the layers being the 4+3 metallic cord.