täyttyy

Täyttyy is a Finnish verb meaning to fill up or to become full. It is intransitive and describes something changing from not full to full or reaching capacity, either in a physical sense (a container, a space, a crowd) or in a figurative sense (a schedule, a period, a phase). The form täyttyy is the third-person singular present indicative of the verb täyttyä. The infinitive is täyttyä; the root is täytty- with the typical Finnish verb endings. Related participles include täyttyvä (present active participle) and täyttynyt (past active participle, used in compound tenses). The verb is contrasted with täyttää, which is transitive and means to fill something.

Common usages include describing processes of filling itself rather than causing the fill. For example, pullo täyttyy vedellä means the bottle fills with water, and sali täyttyy ihmisistä means the hall fills with people. In Finnish, täyttyy is used when the subject undergoes the filling process rather than acting on an object.

Etymology and related forms: the word derives from the root täy-, found in täysi meaning full and täyte meaning filling, with the -ty- suffix forming a verb that conveys becoming full. Related nouns include täyte (filling) and täyttyminen (the act or state of filling).