1. the condition of individuals having several distinct forms (morphs) in the adult stage in the same habitat at the same time, usually with the rarer form at or above some minimum frequency —note 1. polymorphism may be limited to color intensity or patterns, such as in snow geese and many butterflies, or may involve morphology and physiology such as in honeybees and ants —note 2. the term polyphenic is used if the condition is genetically predetermined rather than environmentally induced —see dimorphism 2. nonproportionality of the members of a system of site index or height growth curves This definition last updated 07/30/2008