(Accepted for publication 26 August 2015)

The central aim that animates this paper is to present and discuss the idea of thirdness or analytic third in psychoanalysis, from its origins to the concepts formulated by André Green and Thomas Ogden. The contributions of Winnicott, Reik and the Baranger couple are discussed, as are their influences to contemporary psychoanalysis. In order to promote the clarification and to distinguish different psychoanalytic conceptions of the third, ten figures referring to the meaning of thirdness that appear in different theories are presented, without necessarily their being mutually exclusive. As a final consideration, the article seeks to reorder in four dimensions the ten figures originally presented, emphasizing the central elements in Ogden and Green's constructions. These dimensions are at the same time conceptual and clinical, insofar as they create possibilities of operating the idea of thirdness in the transference/ countertransference dynamics.