þéttni
þéttni is an Old English word. It is the past participle of the verb þéttan, meaning to make tight, to seal, or to stop up. Therefore, þéttni can be understood to mean "tightened," "sealed," or "stopped." The word conveys a sense of closure and prevention of passage.
In Old English literature, þéttni might appear in contexts describing physical barriers, such as a well-sealed