The word battery has several meanings:

1. A device that stores energy and provides electrical power. When you put batteries in a flashlight or remote control, you're giving it the power it needs to work. Batteries come in many sizes, from tiny ones in watches to huge ones in electric cars. Inside a battery, chemical reactions create an electrical current. When a battery runs out of power, we say it's dead or drained. Some batteries can be recharged and used again, while others get thrown away after one use.
2. In law, battery means physically harming someone or touching them without permission. If someone punches another person, that's battery. It's a crime because everyone has the right to feel safe in their own body. The legal term is often paired with assault, which means threatening to harm someone, while battery is the actual harmful contact.
3. In baseball, the battery refers to the pitcher and catcher working together as a team. They're called the battery because they work closely to control the game, deciding what pitches to throw and where.