Polycrystals

Part of speech: noun

Definitions

1. A solid material composed of numerous tiny crystals which are joined together, contributing to its structural integrity
2. A substance formed from multiple crystalline structures, impacting its mechanical properties and behavior
3. An aggregate of numerous crystalline grains, each with different orientations, that collectively define the material's overall characteristics

Etymology: "Polycrystals" is the plural of "polycrystal," a compound built from two parts with a long history of their own. The first part, "poly-," comes from the Ancient Greek "polús," meaning "many" or "much," which English borrowed as a combining form. "Crystal" entered English from Latin "crystallum," itself from Greek "krustallos," meaning ice or rock crystal. Put together, the word literally describes something made of many crystals. The plural form simply counts multiple examples of such materials. Engineers and metallurgists use the word for solids such as metals and ceramics whose structure is built from countless tiny crystal grains packed together at different orientations. Those grain boundaries affect how the material bends, cracks, and conducts heat, which is why the distinction between a single crystal and a polycrystal matters so much in practice.