What does crystalline mean?
"Crystalline" is an adjective describing something that resembles crystal — most often meaning exceptionally clear, transparent, and sparkling. It is frequently applied to natural features such as lakes, streams, glaciers, and winter air, where it conveys purity and brilliance. Beyond this figurative and descriptive sense, "crystalline" has a precise scientific meaning: in chemistry and mineralogy, it denotes a material whose atoms are arranged in a highly ordered, repeating pattern, forming what is called a crystalline structure or lattice. This technical sense contrasts with amorphous materials, which lack such order. The word carries broadly favorable connotations — clarity, purity, precision — whether evoking mountain scenery or describing the atomic geometry of metals and minerals. Derived from the Greek word for ice-like rock crystal, it entered English through Latin and remains valuable both as vivid descriptive language and as essential scientific terminology.
Clear and transparent like crystal.
"The crystalline air after the rain made distant hills seem close enough to touch."
Often used figuratively for anything remarkably pure or clear.
(Of a substance) having the ordered internal structure characteristic of a crystal.
"Silicon is prized in electronics for its nearly perfect crystalline structure."
Common in chemistry, physics, and mineralogy; contrasted with "amorphous."
Quartz watchmakers rely on the crystalline structure of silicon dioxide to keep time with astonishing precision — vibrating tens of thousands of times per second.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of crystalline
"Crystalline" derives from the Greek "krystallos," meaning clear ice or rock crystal, which passed into Latin as "crystallum." The adjective form developed through Late Latin "crystallinus" before entering English, where it was well established by the early modern period. Cognates and derivatives include "crystal," "crystallize," and "crystallography," all tracing back to the same Greek root.
Related word forms
How crystalline is actually used
"Crystalline" often carries a positive, almost poetic connotation when describing water, skies, or voices — suggesting exceptional purity and clarity. In scientific contexts, it is used more technically to describe materials with an ordered atomic arrangement, contrasting with "amorphous" substances.
Easily confused with crystalline
"Crystal" refers to the solid substance itself or a piece of it, while "crystalline" is an adjective describing something that resembles or has the properties of crystal.