A more thorough explanation:

Definition: Case-in-chief refers to the evidence presented by a party during a trial to support their claim or defense. This evidence is presented between the time the party calls the first witness and the time they rest their case. It is the main part of a trial where a party presents their evidence.

For example, in a criminal trial, the prosecution's case-in-chief would include presenting witnesses, physical evidence, and other proof to show that the defendant committed the crime they are accused of. The defense's case-in-chief would include presenting their own witnesses and evidence to refute the prosecution's case and prove the defendant's innocence.

In a civil trial, the plaintiff's case-in-chief would include presenting evidence to show that the defendant is liable for the damages they are seeking. The defendant's case-in-chief would include presenting evidence to refute the plaintiff's claims and show that they are not responsible for the damages.

These examples illustrate how case-in-chief is the main part of a trial where each party presents their evidence to support their claim or defense.