The objective of the paper is the etymology of the Pahlavi judicial term <stwl> conventionally transcribed as stūr. In the first part of the paper a critical review is done of the hypotheses hitherto proposed and a new explanation is given by taking into account Pāzand / New Persian form s(a)tar and Avestan hapax legomenon stūirīm. The new etymology suggests a different Old Persian basic form, than one has believed up to date, as well as a different spelling of the Pahlavi term, i. e. stur. In the second part, a passage of the book Esther is considered and an attempt is made to apply the suggested etymon of Phl. <stwl> for etymological examination of the protagonist's name.