RhymeZone: smectic definitions

Definitions of smectic:

adjective: (rare) Cleansing.
adjective: (rare) Astringent; detergent.
adjective: (chemistry, physics) Describing a class of liquid crystals whose molecules are aligned in layers, with the molecules lying perpendicular to the plane of the layers.
noun: A liquid crystal having the molecules aligned in this way.

(Definitions from Wiktionary)