rakennuksessaan

The Finnish word "rakennuksessaan" is a grammatical form derived from the noun "rakennus," which means "building" or "construction." Specifically, "rakennuksessaan" is the inessive plural form with the possessive suffix for the third person singular. This translates to "in their building" or "within their construction." The inessive case in Finnish indicates a location *inside* something. The plural "rakennuksissa" means "in buildings." Adding the possessive suffix "-an" refers to something belonging to "him," "her," or "them" (singular third person). Therefore, "rakennuksessaan" signifies that a building or construction is in the possession of a singular third-person subject, and the action or state described is happening within that building. For example, "Hän on rakennuksessaan" would mean "He/She is in their building." The context of the sentence clarifies whether "their" refers to a male, female, or a singular entity like a company. This form is commonly used in Finnish to describe locations and possessions related to buildings.