A: A 'motion' is nothing more than a request to the court to take legal action. A 'motion in limine' is a request that the judge act on some piece of evidence, immediately prior to trial. The outcome of such a ruling can have a significant impact on what happens at trial. The attorney may ask for an order preventing another lawyer from bringing in certain evidence. On the other hand, a lawyer may ask for an early ruling on a piece of evidence that has a legal problem.
It allows the attorneys to plan and address strategically what to do in the event an item is not permitted into evidence or alternatively, is permitted.