What is a cross examination?

Answer 1

Cross examination is a part of trial, either civil or criminal. It is the process by which opposing counsel questions a witness after the attorney who called the witness to the witness stand does so. The purpose of cross examination is to cast doubt upon the veracity of the witness' testimony based on one or more bases, including:

1. Inability to accurately recall facts to which he/she testified;

2. bias in favor or against one party;

3. an interest of some kind in the outcome of the case (usually financial or "saving his/her own hide");

4. some other reason that casts doubt on the testimony.

Answer 2

It means to interrogate them by means of questions, asking questions from different angles in order to elicit the truth of the testimony and of the matter being considered.

i.e. to check or extend testimony already given - (Oxford English Dictionary)