tós

Töös is the inessive form of the Estonian noun töö (work). It denotes being in a state of work or that something is currently in progress, rather than simply belonging to a place. It is commonly used to describe ongoing tasks, projects, or other work-related activities.

Formation and usage: The inessive suffix -s attaches to the root noun, yielding töös. It is used for topics like projects or research when they are actively underway. Example: "Projekt on töös" (The project is in progress). "Uurimus on töös" (The study is in progress). For indicating location at a workplace, the related form tööl is used (Ta on tööl = He is at work). The distinction is that töös emphasizes ongoing activity, while tööl marks physical location.

Etymology and status: Töös derives from töö + the inessive suffix -s; it is part of standard Estonian and commonly found in both formal and informal contexts.

See also: Estonian language; Töö; Inessive case.