This article seeks to define the meaning of the rare word , which occurs three times in the Hebrew Bible and seven times in the Dead Sea Scrolls. The evidence of the ancient versions and of certain rabbinic commentators is reviewed in respect of the biblical passages. Where the occurrences of the word in the Dead Sea Scrolls are concerned, the standard English translations by Vermes and García Martínez are considered as well as the opinions of scholars such as Yalon and Licht. The evidence of comparative philology, and in particular of Arabic, has proved to be important and this is set out and illustrated by a number of relevant verses from the Qur’ān. Finally, and in the light of the author’s findings, the descriptions of the word in the standard modern dictionaries and articles are reviewed. The author concludes that the word, in the MT as in the DSS, means ‘concern, preoccupation, (single-minded) devotion’.