Airmass

Part of speech: noun

Definitions

1. A large body of air with uniform temperature and humidity characteristics that influences weather patterns and can be classified into different types based on these traits
2. A defined section of the atmosphere that maintains consistent temperature and moisture content, impacting local weather when it moves or interacts with other air masses
3. An extensive region of air that exhibits homogeneity in temperature and humidity, which plays a crucial role in shaping climatic conditions and weather forecasts

Etymology: The compound is plain: "air" plus "mass", with "mass" in its older sense of a large, coherent body of matter. The meteorological sense is the one that matters here. An airmass is a large body of air that takes on fairly uniform temperature and humidity from the land or sea it sits over, and it keeps those qualities as it moves. Forecasters use the term to name such bodies and to trace how they meet and push against one another. The word may be a calque, a word-for-word copy, of the German "Luftmasse". The two parts are simply translated, so English speakers were building a modern term from familiar materials rather than borrowing a classical one. Readers who know the Latin-based scientific vocabulary of the period will find this a little unusual, since the word is made of two ordinary English words.

Synonyms: air mass