Sentence:  However, the sib and the joint family are two social units differing totally in their structure. For this reason the <WSD>patronymy</WSD> must be borne in mind here. As M. O. Kosven writes, the <WSD>patronymy</WSD> is a group of families, joint or nuclear, that came into being as the result of segmentation of a single patriarchal family commune. 
Meaning of the word marked with <WSD> tags:  An extended family grouping centered around the father's family.