Looking for a proper translation for the concept of a "time-box" in the context of Scrum, I looked up the German word "Frist". The word describes a period of time in which a certain action may (or may not) be taken, it's mostly used in a judicial context.
Inspired by a note on the words roots in Old High German, I consulted Wiktionary, and discovered that the word has siblings in several Germanic languages and is known even in English (albeit obsolete).
I was delighted by the connotations on offer: Throughout the languages, the concept denotes not only an allowance of time, but also signals a respite or truce as well as trust - all of which are on display when mutually agreeing on a time-box in Scrum.
I couldn't wish for a better match.