põhivooluna
Põhivooluna is a Estonian term meaning “as the main current” or “as the main stream.” It is formed from põhivool (main current) with the suffix -una, which expresses the sense of acting in a particular role or capacity. The expression is used to describe how something functions within a larger flow or system.
In hydrology and physical geography, põhivooluna denotes the principal stream or the main channel in a river
Beyond physical contexts, põhivooluna can be used metaphorically to indicate a dominant trend or prevailing direction
The term is most common in formal, technical, or encyclopedic Estonian writing, including hydrological descriptions and