The Collaborative International Dictionary of English v.0.48:

matrilineage \matrilineage\ n.
   The line of descent traced through the maternal side of the
   family; the mother's line of descent.

   Syn: enation, cognation.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

matrilineage
    n 1: line of descent traced through the maternal side of the
         family [syn: matrilineage, enation, cognation]