Anagnorisis:
Anagnorisis translates as "recognition" or "discovery." In tragedy, it describes the moment where the hero, or some other character, passes from ignorance to knowledge. This could be a recognition of a long lost friend or family member, or it could be a sudden recognition of some fact about oneself, as is the case with Oedipus. Anagnorisis often occurs at the climax of a tragedy in tandem with peripeteia.
Peripeteia:
A reversal, either from good to bad or bad to good. Peripeteia often occurs at the climax of a story, often prompted by anagnorisis. Indeed, we might say that the peripeteia is the climax of a story: it is the turning point in the action, where things begin to move toward a conclusion.