Ruohoon

Ruohoon is the illative singular form of the Finnish noun ruoho, meaning grass, lawn, or turf. It is used to express motion toward or into grass.

In everyday Finnish, ruohoon appears with verbs of movement and is common when describing entering or hiding in grass. For example, perhonen piiloutui ruohoon, meaning "the butterfly hid in the grass." The form is created by adding the illative suffix -on to the stem ruoho.

Ruoho is a basic noun with several inflected forms: nominative ruoho, genitive ruohon, inessive ruoossa, elative ruoosta, and illative ruohoon. The illative -on follows vowel-ending stems and is one of several illative patterns in Finnish that convey direction or destination toward something.