Castration in a dream: what does it mean?
A dream of losing a part of the body carries the fear of permanent diminishment, and Freud built so much on this image that reading it now requires separating him from it.
How do the four traditions read it?
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream. The four often disagree, and that is the point: a symbol rarely means one fixed thing, and the distance between Freud, Jung, modern research and myth tells you more than any single verdict could.
Freud
This is central to Freud and it is also among the parts of his work that has worn worst. He treated the fear as a universal developmental stage; most of his own field no longer does. The idea is recorded here because his account cannot be read without it, not because it is endorsed.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
For Jung the loss of a bodily part can image a capacity the dreamer feels has been taken, and the reading works without any of Freud's specific machinery, which is part of why it has lasted better.
Our summary of a Jungian reading, in our own words, not Jung's. See Jung, ed., Man and His Symbols (1964).Modern
Under the continuity view these tend to follow real surgical anxiety, real illness and real fear of loss. The plain reading matters: anyone dreaming this before or after a procedure is dreaming about the procedure.
Our summary of the continuity hypothesis, named by Calvin Hall and Vernon Nordby, The Individual and His Dreams (1972). Its correct scope is disputed; see Domhoff (2017) and the replies to him.Mythological
Ritual and punitive castration are both historically attested and the traditions around them are about control of lineage and of labour, which is a bleaker and more accurate frame than the symbolic one.
Rosmerta Publishing editorial synthesis (after Frazer; Bulfinch).How can writers use this symbol?
The same symbol, read as craft material rather than as a dream. What it does on the page, how genres use it differently, and what happens when you turn it inside out. Written for novelists, screenwriters and poets who need the symbol to actually work, and it ends with something to try.
In literature
The image is so freighted with a single theory that fiction using it is usually arguing with Freud whether or not the writer intends to.
Rosmerta Publishing editorial synthesis. Our own words; no quoted text.What it does in a story
It threatens a permanent alteration rather than death, which is a different and in some ways harder stake. Structurally it is a threat rather than an event in most fiction.
Genre conventions
Psychoanalytic fiction uses the theory. Historical fiction uses the practice. Medical writing uses the surgery, which is routine, therapeutic and almost never written.
How to subvert it
Write somebody who has had the surgery for medical reasons and is entirely uninterested in what it symbolises.
Try this
Write a consultation before a procedure. Only the clinician's explanation and the patient's questions.
Only the first of these names a source. What a symbol does in a story, how genres treat it, how to invert it and what to try are our editorial judgement as writers and editors, not findings from a body of research. They are offered as craft opinion and should be argued with.