In Japanese, it actually means something close to "head of the household", and is related to a term that was used in feudal Japan to refer to the head of the family of a feudal lord.

Apparently, the term was not used in bujutsu until the Meiji Period, when the soke system was adopted for styles/schools to centralize control over associated dojo throughout the country.

The kanji is used in other compounds as Tashigae said. In Japanese, for example, the words for "author" "painter" and "politician" among others.