tonitro-, tonitru- +

1. A booming or crashing noise caused by air expanding along the path of a bolt of lightning.
2. Noise resembling thunder; such as, a loud deep rumbling noise resembling thunder.
3. A manifestation of someone's anger in an explosion of strong words.
4. Etymology: from Middle English thuner, later thunder which came from Old English žunor, from Proto German thunraz, "to resound", "to thunder". It is also believed to be from a distant Latin tonare, "to thunder", tonitrus, "thunder".

Thunder is the sound emitted by rapidly expanding gases along the channel of a lightning discharge. Over three-quarters of lightning's electrical discharge is used in heating the gases in the atmosphere in and immediately around the visible channel.

Temperatures can rise to over 10,000 degrees centigrade in microseconds, resulting in a violent pressure wave, composed of compression and rarefaction.

The rumble of thunder is created as one's ear catches other parts of the discharge, the part of the lightning flash nearest registering first, then the parts farther away.

To thunder.

An excessive fear of thunder.

Full of or characterized by thunder, loud noise, or violent utterance; thundery; thundering.

Pertaining to, or loaded with, thunder.

Thundering.

A device for imitating thunder.

1. An extremely destructive funnel-shaped rotating column of air that passes in a narrow path over land.
2. A short-lived but severe windstorm, especially one that occurs on the West African coast.
3. A state of frenzied activity or intense emotion, or someone in such a state.
4. Etymology: from 1556, a navigator's word for violent windy thunderstorm in the tropical Atlantic, probably a borrowing from Spanish tronada, "thunderstorm", from tronar, "to thunder"; from Latin tonare, "to thunder".

Tornadoes occur chiefly during thunderstorms. If the tip of the funnel touches the ground, it can cause extensive damage.

A tornado becomes visible when a condensation funnel made of water vapor (a funnel cloud) forms in extreme low pressures, or when the tornado lifts dust, dirt, and debris upward from the ground.

A mature tornado may be columnar or tilted, narrow or broad; sometimes so broad that it appears as if the parent thundercloud itself had descended to ground level.