>discovery
Discovery
To begin preparing for trial, both sides engage in discovery . This is the formal process of exchanging information between the parties about the witnesses and evidence they’ll present at trial.
Discovery enables the parties to know before the trial begins what evidence may be presented. It’s designed to prevent "trial by ambush," where one side doesn’t learn of the other side’s evidence or witnesses until the trial, when there’s no time to obtain answering evidence.
https://www.americanbar.org/groups/public_education/resources/law_related_education_network/how_courts_work/discovery/