The Collaborative International Dictionary of English v.0.48:

Coparcenary \Co*par"ce*na*ry\
   (k[-o]*p[aum]r"s[-e]*n[asl]*r[y^]), n.; pl. Coparcenaries
   (-r[i^]z). [Pref. co- + parcenary] (Law)
   Partnership in inheritance; joint heirship; joint right of
   succession to an inheritance.
   [1913 Webster]