küllastunud

Küllastunud is Estonian for saturated or filled to capacity. It is a general descriptive term used across disciplines to indicate that something has reached its maximum amount or cannot absorb more under the given conditions. The nuance depends on the context, but the core idea is fullness or completion.

In chemistry, küllastunud describes substances with no available capacity to bond with more atoms under the specified conditions. Küllastunud süsivesinikud typically refer to alkanes, hydrocarbons where carbon atoms are linked by single bonds and each carbon is bonded to the maximum number of hydrogen atoms. In nutrition, küllastunud rasvad are fats that predominantly contain fatty acids with only single bonds; they are usually solid at room temperature. These fats are contrasted with küllastumata (unsaturated) fats, which have one or more carbon–carbon double bonds.

In solution chemistry, a küllastunud lahus is a solution that contains the maximum possible amount of dissolved solute at a given temperature. Adding more solute causes precipitation or undissolved solid to remain.

In meteorology, a gas or air is said to be küllastunud when it is fully saturated with water vapor, meaning the relative humidity is 100 percent and the air cannot hold more water at that temperature.

Etymology: the word derives from küllastus, meaning saturation, with the suffix -unud forming an adjective. The term is used across science, nutrition, and everyday language to indicate that a system has reached its limit or capacity.