organizer /ôr″gənī′zər/ [Gk, organon + izein, to cause] , (in embryology) any part of the embryo that induces morphological differentiation in some other part. Those parts that are formed and in turn give rise to other parts are classified as organizers of the second degree, third degree, and so on as the embryo develops in complexity. Kinds include nucleolar organizer, primary organizer.
