Definition
Having the regular, repeating internal atomic structure of a crystal. A crystalline material has its atoms or molecules arranged in an orderly, predictable pattern rather than scattered randomly.
Plain English
Made of tiny building blocks stacked in a neat, repeating pattern. The orderly arrangement is what makes the material behave the way it does.
Context Anchor
Seen in aviation weather, icing, and aircraft maintenance discussions when describing ice particles, deposits, or material structure.
Derivation
From the Greek 'krystallos,' originally meaning 'ice' or 'clear ice,' later used for clear quartz and other naturally formed mineral structures. The word came to describe anything with that same kind of regular internal order, even when the material itself isn't transparent.
Why Pilots Care
Crystalline ice changes airflow and adds weight more unpredictably than smooth clear ice, so pilots must recognize it quickly to decide whether to exit icing conditions or activate de-icing equipment.
Intuition Check
Do not read crystalline as simply meaning clear or glass-like. In this context, it means crystal-structured or crystal-shaped, even if the material is cloudy, white, or opaque.
Example Sentence 1
The crystalline structure of the metal changed after prolonged heating, reducing its strength.
Example Sentence 2
Crystalline frost on the propeller blades must be completely removed before engine start.