Source : Webster's Revised Unabridged Dictionary (1913)

Polyandry \Pol`y*an"dry\, n. [Poly- + Gr. ?, ?, man, male: cf.
   F. polyandrie.]
   The possession by a woman of more than one husband at the
   same time; -- contrasted with {monandry}.

   Note: In law, this falls under the head of polygamy.

Source : WordNet®

polyandry
     n : having more than one husband at a time