The word charger has several meanings:

1. A device that restores electrical power to batteries. When your tablet's battery runs low, you plug it into a charger to refill it with electricity. Phone chargers, laptop chargers, and electric car chargers all work the same basic way: they transfer electrical energy from a power source into a rechargeable battery. The charger for your wireless headphones might be a small cable, while the charger for an electric vehicle might look more like a gas pump.
2. A large, flat plate used for serving food or as decoration under regular dinner plates. At a fancy dinner, you might see a decorative charger plate beneath each person's regular plate. These chargers, often made of metal, wood, or ceramic, make the table setting look elegant. They're usually removed before the main course is served.
3. A powerful horse trained for battle. Medieval knights rode chargers into combat because these horses were strong, fast, and brave enough to charge toward enemy lines.