Sentence:  This close <WSD>family grouping</WSD> may be a fairly recent development, for Lang and Tastevin (1937, p. 70) report that the Mwila once lived in villages of fifteen or twenty families consisting of approximately one hundred people and that, at the time they were writing, five or six families still grouped around a chief. 
Meaning of the word marked with <WSD> tags:  The method in which individuals are grouped together into families that live together.