Definition

Noun: A large, rounded, and often anvil-shaped top of a cumulus cloud, typically with bright, well-defined edges. It is the upper portion of a cumulus cloud that has grown into a cumulonimbus cloud and is frequently observed as a precursor to a thunderstorm.

Usage

The term "thunderhead" is used specifically in meteorology and general weather observation to describe the distinctive, towering cloud formation associated with the development of severe weather. It is a visual indicator of atmospheric instability.

Examples

• From a distance, we could see a massive thunderhead building on the horizon.
• The pilot changed course to avoid the dark thunderhead ahead.
• That thunderhead looks menacing; we should head indoors soon.

Advanced Usage

• Descriptive Use: The term is often used descriptively to emphasize the size, shape, or threatening nature of a cloud.
  • The sky was dominated by a single, brooding thunderhead.

Variants and Related Words

• Cumulonimbus Cloud (n): The full, mature cloud type of which a thunderhead is the prominent upper part. A thunderhead is a visual feature of a cumulonimbus cloud.
• Anvil Cloud (n): A synonym often used interchangeably with "thunderhead," referring specifically to the anvil-like shape at the top of a mature cumulonimbus.

Synonyms

• Anvil cloud
• Cumulonimbus top
• Storm cloud (a more general term for any cloud associated with a storm)

Antonyms

• Clear sky
• Fair-weather cloud (e.g., small cumulus humilis)

Noun

1. a rounded projecting mass of a cumulus cloud with shining edges; often appears before a thunderstorm