In the United States, they call them depositions.
In Ontario, they are referred to as Examinations for Discovery, or Discoveries, or Discovery.
Examinations for Discovery take place under oath. That means that the deponent has to swear, or affirm, that they will tell the truth (not lie!).
They are an opportunity for the other side to ask questions about your case. They will ask all sort of questions about you as well. Some questions may be relevant to your case. Other questions may not appear to be relevant, but sometimes are. It’s best to trust you lawyer to determine which questions you ought to answer, and which questions you ought to refuse to answer. In the event that there’s a disagreement about what’s relevant, and what’s not relevant, the lawyers will identify the question as a “refusal“. It then would be up to a Judge to decide whether or not the question needs to be answered, and whether or not the deponent would need to re-attend at discovery based on the answer to the question refused. This is a common occurrence at Examinations for Discovery. Lawyers tend to agree to disagree, and move on in order to complete the Examination for Discovery; and then argue about the refusals later. It makes no sense to spend all day and waste time arguing refusals at the discovery itself when a Judge will ultimately have the final say in terms of whether or not the question needs to be answered and addressed or not.