läpimenevissä

Läpimenevissä is a Finnish adjective form used to describe materials or media that allow passage through them. The word is derived from the root läpi- meaning “through” and menevä, and the form -issä signals a plural inessive context, so it is typically found with plural nouns in phrases such as läpimenevissä kerrostumissa or läpimenevissä materiaaleissa.

Läpimenevä describes permeability to various substances, most commonly light, gas, or fluids, but the exact meaning depends on the substance in question. In scientific Finnish it is often used interchangeably with läpäisevä, though läpimenevä can emphasize the through-going nature of the permeability.

Common usage domains include geology, hydrogeology, and material science. In geology and hydrogeology it may refer to permeable rock layers or aquifers where fluids can migrate through pores or fractures. In material science and engineering it can describe membranes or filters designed to permit specific substances to pass while blocking others. Environmental science and engineering also employ the term when discussing pollutant transport through soils or sediments.

Limitations and context are important: permeability is substance-specific, so a material described as läpimenevissä to liquids may not be equally permeable to gases, and vice versa. The precise interpretation relies on the target substance and the experimental or observational conditions.

See also: läpäisevä, permeability, permeation, filtration.