The term “limine,” from the Latin limen, meaning “threshold,” generally refers to a motion made shortly before the start of evidence in a trial.
There is no specific statutory authority for the motion in limine, but Rules of Court, Rule 31112(f) implicitly recognizes the motion by providing that “a motion in limine filed before or during trial need not be accompanied by a notice of hearing. The timing and place of the filing and service of the motion are at the discretion of the trial judge.” Several other rules also implicitly recognize motions in limine (see Rules 3.20, 3.670, 3.1547, etc.).
Many issues are the proper subject of motions in limine, but the most common use of in limine motions is to prevent the jury from receiving unfavorable evidence. The court has discretion to rule on evidentiary matters before the jury has a chance to even learn of their existence (Evidence Code §402; People v. Jennings (1988) 46 Cal. 3rd 963).
Other proper subjects for motions in limine stem from the court’s power to “Provide for the orderly conduct of proceedings before it” (Code of Civil Procedure §128(a)(3)) and to “Control its process and orders so as to make them conform to law and justice” (id. §128(a)(8)).
The court in Kelly v. New West Federal Savings (1996) 49 Cal. App. 4th 659 explained motions in limine:
In recent years, the use of motions in limine has become more prevalent, primarily by defense counsel to address a number of perceived concerns. It is not uncommon for the trial court to be presented with in excess of 10 separate motions in limine…
Motions in limine are a commonly used tool of trial advocacy and management in both criminal and civil cases. Such motions are generally brought at the beginning of trial, although they may also be brought during trial when evidentiary issues are anticipated by the parties. In either event, they are argued by the parties, either orally or in writing or both, and ruled upon by the trial judge. The usual purpose of motions in limine is to preclude the presentation of evidence deemed inadmissible and prejudicial by the moving party. A typical order in limine excludes the challenged evidence and directs counsel, parties, and witnesses not to refer to the excluded matters during trial. The advantage of such motions is to avoid the obviously futile attempt to “unring the bell” in the event a motion to strike is granted in the proceedings before the jury.
Motions in limine serve other purposes as well. They permit more careful consideration of evidentiary issues than would take place in the heat of battle during trial. They minimize side-bar conferences and disruptions during trial, allowing for an uninterrupted flow of evidence. Finally, by resolving potentially critical issues at the outset, they enhance the efficiency of trials and promote settlements.”
The above is taken from California Criminal Defense Motions in Limine, which contains a large collection of sample Motions in Limine. This book, however, only gives a cursory overview of Motions in Limine.