Sentence:  The visual moment whose consequences Freud began to ponder in the essay on the phallic stage has evolved into a <WSD>peripeteia</WSD>: "Some day or other it happens that the child whose own penis is such a proud possession obtains a sight of the genital parts of a little girl; he must then become convinced of the absence of a penis in a creature so like himeself. With this, however, the loss of his own penis becomes imaginable, and the threat of castration achieves its delayed effect." 
Meaning of the word marked with <WSD> tags:  A turning point in psychosocial development. (from 1960s)