The nipple occupies a theoretically charged locus in depth-psychological discourse, operating simultaneously as anatomical referent, object-relational anchor, and symbolic vehicle. Freud established the foundational framework in the Three Essays, where the nipple’s erotogenic function initiates infantile sexuality as auto-erotic activity that only secondarily attaches to an external object; the breast-nipple complex thus marks the inaugural site where drive and object first converge. Klein extended this considerably: for her, the nipple is the concrete face of the ‘good’ or ‘bad’ breast, and the infant’s biting of it expresses the earliest sadistic impulses that inaugurate the paranoid-schizoid position. Abraham mapped nipple-genital displacement, noting that patients who unconsciously equate the small nipple with the penis manage castration anxiety through this topographical substitution. Beyond the clinical literature, the nipple figures archetypally in Neumann’s Great Mother as part of the breast-vessel-milk symbolism complex, and in Hillman’s alchemical hermeneutics as a site of ‘tasted knowledge’—sapientia delivered directly to the body. Neurobiologically, Panksepp’s work on the suckling reflex identifies the nipple as the sensory trigger for oxytocin release, linking it to the entire mammalian affiliative system. Across these varied registers, the central tension is between the nipple as part-object (Klein, Abraham) and the nipple as relay in a symbolically elaborated field of nourishment, wisdom, and primary relatedness.