Electrons: 
A sub-atomic (really, really small) particle that carries a negative energy charge. 

Leaders: 
A channel of charged air created by excess electrons in a thunderstorm cloud. A leader reaches from the cloud to the ground below, looking for positive charges. 

Lightning: 
Any visible electrical discharge produced by positively charged and negatively charged areas in a thunderstorms. 

Protons: 
A sub-atomic (really, really small) particle that carries a positive energy charge. 

Return Stroke: 
An electrical charge that travels from the ground to a thundercloud. This return stroke releases tremendous energy, bright light and thunder. 

Static Electricity: 
A form of electricity that is created when an object has too many electrons, giving it a negative charge. 

Streamers: 
A channel of charged air created by protons on the ground. They are created when leaders are created, and reach from the ground to the sky looking for a leader to connect with. 

Thunder: 
The sound that follows a flash of lightning and is caused by sudden expansion of the air in the path of the electrical discharge.