Glossary
Deposition
A pre-trial questioning of a witness, in person and under oath, with a court reporter creating a transcript. Used in discovery to find out what a witness will say at trial: and sometimes to use the transcript at trial if the witness can't appear.
Depositions usually happen in a lawyer's office, not a courtroom. The witness sits at a table with the court reporter, and lawyers from each side ask questions. The whole thing is recorded by the court reporter and later transcribed.
Depositions can last a few hours or several days. The witness has to answer (with limited exceptions like privilege), and lying under oath in a deposition is the same crime as lying in court: perjury.
Deposition transcripts get used a lot. They're how lawyers prep for trial, impeach witnesses who change their stories, and create the record for summary judgment motions.