Heteroecious \Het`er*[oe]"cious\, a. [Hetero- + Gr. ? house.] (Bot.) Passing through the different stages in its life history on an alternation of hosts, as the common wheat-rust fungus ({Puccinia graminis}), and certain other parasitic fungi; -- contrasted with {aut[oe]cious}. -- {Het`er*[oe]"cism}, n. [Webster 1913 Suppl.]