The Collaborative International Dictionary of English v.0.48:

patrikin \patrikin\ n.
   one related on the father's side.

   Syn: agnate, patrilineal kin, patrisib, patrilineal sib.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

patrikin
    n 1: one related on the father's side [syn: agnate,
         patrikin, patrilineal kin, patrisib, patrilineal
         sib]