battery

Everyday

1. A small object that stores electricity and gives it to torches, toys, phones and remote controls. tree →
2. A row or group of similar things: "a battery of tests". tree →
3. (In law) the crime of hitting someone. tree →
4. A set of large guns. tree →

In the lessons

In science, a battery (cell) pushes electricity around a circuit; it stores chemical energy and changes it to electrical energy; it has + and − ends. In safety: button batteries are very dangerous if swallowed — get help at once; don't put batteries in fire; recycle used batteries. Phrases: battery-powered, flat battery (empty), rechargeable battery, charge the battery.

Examples

• The torch needs a new battery. tree →
• My phone battery is flat. tree →
• A battery has a plus end and a minus end. tree →
• Button batteries are dangerous if swallowed. tree →
• Recycle old batteries. tree →
• The toy runs on two batteries. tree →
• Connect the battery to the bulb to make a circuit. tree →
• Charge the battery overnight. tree →

Note

Plural "batteries" (y → ies). Scientists call one unit a "cell"; a battery is really two or more cells, but in everyday English one is called a battery. A swallowed button battery is an emergency.