driest

Driest is the superlative form of the adjective dry. It describes the greatest degree of absence of moisture within a group of objects, places, or times. Driest is used when comparing three or more items or occasions, to indicate that one is more dry than the others.

In meteorology and climatology, driest conditions refer to the lowest humidity, precipitation, or soil moisture within a geographic area or time period. Descriptions such as the driest month or the driest desert are common. Dryness is typically quantified by measures such as total annual precipitation, relative humidity, dew point, or vapor pressure deficit.

In agriculture, food processing, and materials science, dryness affects storage, quality, and behavior. Drying processes reduce moisture content to reach a target dryness level; dryness is expressed as a moisture percentage or dryness fraction in some engineering contexts. A dryness fraction of one denotes completely dry steam, whereas lower values indicate the presence of liquid water.

Etymology and usage notes: driest derives from the adjective dry with the superlative suffix -est; the comparative form is drier (or dryer in some senses). The word is commonly used with nouns that are countable or with uncountable contexts to indicate the utmost lack of moisture within a set.

See also dryness, aridity, desiccation, humidity, moisture.