läpäisevän

Läpäisevä is a Finnish adjective meaning permeable or penetrable, used to describe a material, membrane, or layer that allows passage of substances such as liquids, gases, or signals. The form läpäisevän is the genitive singular of the adjective and is used when describing a noun in genitive, for example läpäisevän kalvon ominaisuudet (the properties of the permeable membrane). The related noun forms are läpäisevyys (permeability) and läpäisy (permeation).

Etymology and meaning: läpäisevä is built from the verb läpäistä (to permeate, to pass through) with the adjectival suffix -vä, producing a term that denotes a property enabling passage. The concept is widely used in technical Finnish.

Usage and contexts: The term is common in science and engineering, including biology, chemistry, materials science, and membrane technology. In textiles, läpäisevä or hengittävä fabrics describe materials that allow water vapor to pass, contributing to comfort. In membranes and coatings, läpäisevyys denotes the rate or extent to which substances cross the barrier. The word can also appear in everyday language when discussing air or moisture permeability, though it is more technical than everyday synonyms.

See also: läpäisevyys, läpäisy, diffuusio, osmoosi, kalvo, hengittävä.