nähdessään

nähdessään is a Finnish language grammatical form. It is the third infinitive, past tense, adessive case of the verb nähdä, meaning "to see". This form translates to "upon seeing", "when seeing", or "in the act of seeing". It is used to indicate an action or state that occurs at the same time as or immediately following another action, where the subject of both actions is the same. For example, "Hän hymyili nähdessään ystävänsä" translates to "He smiled upon seeing his friend". The structure involves the verb stem, the passive past participle ending "-ss-", and the adessive case ending "-än". This grammatical construction is common in Finnish and allows for concise expression of simultaneous or sequential events. It connects the action of seeing directly to the subsequent or concurrent reaction or observation. Other verbs can also take this form, following the same grammatical pattern to express a similar temporal relationship. The form emphasizes the immediacy of the reaction to the act of seeing.