noun
: a plant or animal species so highly adapted to a particular kind of environment that its presence is sufficient indication that a habitat under investigation belongs to the kind to which the species is adapted
noun
: a plant or animal species so highly adapted to a particular kind of environment that its presence is sufficient indication that a habitat under investigation belongs to the kind to which the species is adapted
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012