efflorescere

Efflorescere is a Latin verb meaning “to bloom forth” or “to flower.” The term is formed from the Latin root for flower (flor) and the prefix ex- indicating outwardness. In classical Latin usage it described plants coming into flower, and the word is the source of later Romance-language forms and the English noun and verb efflorescence/effloresce.

In English, effloresce serves as a technical verb in two main senses. A botanical sense, inherited from the Latin, can be used poetically or historically to mean to come into bloom. More commonly in modern technical usage, effloresce means to form or deposit crystals on a surface as water evaporates from a hydrated salt; the process is called efflorescence, and the resulting white or pale crusts are often described as efflorescence on masonry or minerals.

The noun efflorescence designates both the phenomenon and the deposit itself. In mineralogy and chemistry, it refers to the outward crystallization of salts that have lost water of crystallization. In architecture and building diagnostics, efflorescence describes white, powdery, crusty salt deposits that can appear on bricks, stone, concrete, or tile, typically driven by moisture movement and salt content in the material or surrounding environment.

Etymologically, efflorescere is the ancestor of the English verb effloresce and the noun efflorescence, and it appears in literary and scientific contexts to describe flowering in plants or the outward crystallization of salts. See also efflorescence.