A more thorough explanation:

In a civil lawsuit, an interrogatory is a set of questions that one party sends to the other party as part of the discovery process. The recipient must answer the questions under oath and according to the case's schedule. Attorneys may help their clients answer interrogatories, so the responses tend to be more carefully crafted than answers to deposition questions. The number of questions included in an interrogatory is usually limited by court rule.

For example, under the Federal Rules of Civil Procedure, each party may only ask each other party 25 questions via interrogatory unless the court gives permission to ask more. Interrogatory rules vary by jurisdiction.

Here is an example of an interrogatory:

Question: Please describe in detail the events that led up to the car accident on June 1, 2021.

Answer: On June 1, 2021, I was driving my car on Main Street when another car ran a red light and collided with my vehicle. I had no time to react and was unable to avoid the accident.

This example illustrates how an interrogatory is used to gather information about a specific event or situation related to the lawsuit. The recipient of the interrogatory must provide a detailed and truthful response under oath.