LOL; in limine literally means: on the threshold; at the beginning.
It is a motion filed shortly before the hearing (with no trial) or trial (before jury). "Immediately, upon seeing the words Motion in Limine in the motion’s Caption, the judge knows it deals with evidence and with how it will be handled at trial."
This website discusses a bit better than I can:
Motions in Limine are called “threshold motions” that anticipate and seek to control the trial’s conduct. It is equitable in nature and therefore well within the court’s discretion to grant or deny. It is a useful and powerful device to assure a fair trial, but is rarely the basis for a reversal on appeal – indeed, though there may be some, I am unaware of any case reversed solely because the court denied a Motion in Limine.