“Symbolic castration - the final moment of analysis is reached when the subject is ready to accept this fundamental loss, to consent to symbolic castration as a price to be paid for access to his desire.”

[4] Symbol
Semiotics and the Philosophy of Language (1984)
Context: What is a symbol? Etymologically speaking, the word σύμβολον comes from σνμβάλλω, to throw-with, to make something coincide with something else: a symbol was originally an identification mark made up of two halves of a coin or of a medal. Two halves of the same thing, either one standing for the other, both becoming, however, fully effective only when they matched to make up, again, the original whole. … in the original concept of symbol, there is the suggestion of a final recomposition. Etymologies, however, do not necessarily tell the truth — or, at least, they tell the truth, in terms of historical, not of structural, semantics. What is frequently appreciated in many so-called symbols is exactly their vagueness, their openness, their fruitful ineffectiveness to express a 'final' meaning, so that with symbols and by symbols one indicates what is always beyond one's reach.

Source: The Purpose Driven Life: What on Earth Am I Here for?

Source: My Years with General Motors, 1963, p. 173 (2015 edition)

On the Uses and Transformations of Linear Algebra (1875)
Context: The familiar proposition that all A is B, and all B is C, and therefore all A is C, is contracted in its domain by the substitution of significant words for the symbolic letters. The A, B, and C, are subject to no limitation for the purposes and validity of the proposition; they may represent not merely the actual, but also the ideal, the impossible as well as the possible. In Algebra, likewise, the letters are symbols which, passed through a machinery of argument in accord ance with given laws, are developed into symbolic results under the name of formulas. When the formulas admit of intelligible interpretation, they are accessions to knowledge; but independently of their interpretation they are invaluable as symbolical expressions of thought. But the most noted instance is the symbol called the impossible or imaginary, known also as the square root of minus one, and which, from a shadow of meaning attached to it, may be more definitely distinguished as the symbol of semi-inversion. This symbol is restricted to a precise signification as the representative of perpendicularity in quaternions, and this wonderful algebra of space is intimately dependent upon the special use of the symbol for its symmetry, elegance, and power.

that is, the lack in the Other.
148
The Sublime Object of Ideology (1989)

Wake Up To Your Life. (2002) pg. 264. (Topic: Awareness)

in a letter to Alfred H. Barr, Jr. 6 November, 1955; as quoted in Abstract Expressionism, Barbara Hess, Taschen, Köln, 2006, p. 34
Baziotes' quote is referring to his painting 'Pompeii', Baziotes painted in 1955
1950s

30 December 1850
Journal Intime (1882), Journal entries
Context: Everything which is, is thought, but not conscious and individual thought. The human intelligence is but the consciousness of being. It is what I have formulated before: Everything is a symbol of a symbol, and a symbol of what? of mind.

Part 2, 00:30:25
Part 2: "The Virus Of Faith", quoted at ibid.
The Root of All Evil? (January 2006)