Thunderstorm :
A storm with lightning and thunder is called a thunderstorm.It is a high speed wind which occurs due to the convection of air in hot and humid areas.
Cyclones :
A natural calamity caused by difference in air pressure in the atmosphere is called a cyclone.In this wind moves in circle around the center of low-pressure.The formation of a cyclone depends on the speed and direction of the wind, temperature and humidity.
Cyclones are formed from simple thunderstorms. Tropical cyclones form due to latent heat driven by significant thunderstorm activity.
However, these thunderstorms can only grow to cyclone strength with cooperation from both the ocean and the atmosphere. For this the ocean water itself must be warmer than 26.5 degrees Celsius. The heat and moisture from this warm water is ultimately the source of energy for cyclones.