英：order; 法：ordre
虽然拉康从很早开始便在其著作中使用“实在”“象征”与“想象”这些术语，但是直到1953年，他才开始把这些概念说成是三大“秩序”或是三大“辖域”(registers)。从此时起，它们便渐渐变成了他的全部理论化皆围绕其运转的基础分类系统。
想象界 (IMAGINARY)、象征界 (SYMBOLIC)与实在界（REAL)因而便构成了一个基本分类系统，从而使我们得以在一些概念之间做出重要的区分，根据拉康的观点，这些概念在先前的精神分析理论中皆是有所混淆的。例如，拉康指出，大量的误解出现在精神分析理论之中，皆是由于未能区分想象的父亲、象征的父亲与实在的父亲。因而，拉康便宣称他的三重分类系统无可估量地阐明了弗洛伊德的著作：“倘若没有这三个系统的引导，我们便不可能对弗洛伊德的技术与经验做出任何理解。”(S1,73)
想象界、象征界与实在界具有极端的异质性，每一秩序皆指涉精神分析经验中截然不同的面向。因此，我们便很难看到它们的共同之处，然而，拉康将此三者皆称作“秩序”的这一事实却也暗示出它们共有着某种共同属性。在1974一1975年的研讨班上，拉康便借由博洛米结 (BORROMEAN KNOT)的拓扑学来探讨三大秩序的共同之处。它们并非像弗洛伊德结构模型中的三大机构 (gencies)那样的心理力量。然而，它们皆主要关涉心理的运作，且三者共同涵盖了精神分析的整个领域。
尽管三大秩序有着极端的异质性，但是每一秩序必须通过参照于其他两个秩序来界定。博洛米结便阐明了三大秩序在结构上的相互依存，其中的三个圆环有任何一者断裂，皆会导致另外两个圆环也分离开来。
(ordre) Although Lacan uses the terms 'real','symbolic'and 'imaginary'from early onin his work, it is not until 1953 that he speaks of these as three 'orders'or three 'registers'. From that moment on they come to be the fundamental classification systemaround which all his theorising turns.
The IMAGINARY, the SYMBOLIC and the REAL thus comprise a basicclassification system which allows important distinctions to be drawn between conceptswhich, according to Lacan, had previously been confused in psychoanalytic theory. Forexample Lacan argues that much misunderstanding has arisen in psychoanalytic theorydue to a failure to distinguish between the imaginary father, the symbolic father and thereal father. Thus Lacan claims that his tripartite classification system has shed invaluablelight on Freud's work: 'Without these three systems to guide ourselves by, it would beimpossible to understand anything of the Freudian technique and experience' (S1,73)
The imaginary, the symbolic and the real are profoundly heterogeneous, each referringto quite distinct aspects of psychoanalytic experience. It is therefore difficult to see whatthey have in common, and yet, the fact that Lacan refers to all three as 'orders'impliesthat they share some common property. Lacan explores this question of what the threeorders have in common by means of the topology of the BORROMEAN KNOT in his1974-5 seminar. They are not mental forces like the three agencies in Freud's structuralmodel. However, they are primarily concemned with mental functioning, and together theycover the whole field of psychoanalysis.
Although the three orders are profoundly heterogeneous, each order must be definedby reference to the other two. The structural interdependence of the three orders isillustrated by the Borromean knot, in which the severing of any one of the three ringscauses the other two to become separated also.