kiirgustel

Kiirgustel is the adessive plural form of the Estonian noun kiirgus, which means "radiation" or "emission." In Estonian grammar the adessive case typically expresses location, accompaniment or the notion "on/at/by," and the adessive plural therefore conveys meanings such as "on the radiations," "at the radiations," or "with the radiations" when referring to multiple instances or types of radiation.

The form is used in both technical and everyday contexts. In scientific writing and speech it can appear in phrases describing measurements, observations or effects related to various radiative sources (for example, instruments placed at or measurements taken on different radiations). In general usage it functions like other adessive plural forms to locate actions or states with respect to the plural referent.

Etymologically, kiirgus derives from the verb kiirgama ("to radiate"); kiirgustel is produced by applying the adessive case to the plural stem of that noun. As with other Estonian case forms, its exact translation into English depends on context, and it is primarily meaningful within whole phrases or sentences rather than as an isolated lexical item.