The destiny of the "Born Innocent" television violence trial may be determined tomorrow, when the judge is to announce his ruling on what he calls "the most important issue": whether to adopt a radically new interpretation of the kind of constitutionally unprotected speech known as "incitement."

The announcement likely will decide whether the jury will bear evidence in the unprecedented $11 million damage suit brought by a child rape victim against NBC, or whether it will be dismissed and the ruling appealed.

During a three-hour pretrial skirtmish Friday, NBC attorney Floyd Abrams urged superior Court Judge Robert L. Dossee to adopt the Supreme Court's definition of incitement given in 1969 decision: "Advocacy . . . directed to inciting or producing imminent lawless action and . . . likely to incite or produce such action."

If the judge adopts this definition, Marvin E. Lewis, attorney for the victim, would have to show that she was raped by other children - with a blunt instrument, in a manner similar to that in a scene in "Born Innocent" - because NBC intentionally had advocated the commission of such a crime when it aired the two-hour TV drama in September 1974.

Lewis not only makes no such charge against NBC, but says it would be impossible to prove. Rather, his contention is that NBC was negligent and reckless in showing, during early night hours, when large numbers of youngsters were watching, a rape scene it should have foreseen would be imitated.

He urged Dossee to rule that there is "a new type of incitement," harmful to youngsters, under which he would have to prove negligence and recklessness, not advocacy and intent.

Such a ruling, Lewis told the judge, would properly balance the First Amendment against the right of youngsters in their homes to be protected from "excitation" by TV programs that can stimulate criminal acts. NBC knew or should have known that youngsters in the "Born Innocent" audience were ready to imitate the "novel" rape, he contended.

Dossee said he will announce his ruling at 1 p.m. (EST), four hours before the jury, empaneled Thursday, is to start to sit and hear Lewis' opening statement.

If the judge adheres to the 1969 Supreme Court decision, NBC's Abrams said, he will move after Lewis' opening statement to have the case thrown out as a "non-suit" Lewis has conceded he can't prove incitement by that standard. Abrams emphasized.

Lewis, agreeing there is "no way" he could prove incitement by that standard, announced that he will not try the case if it is adopted, Instead, he told the judge, he would appeal such a ruling.

In urging Dossee to redefine incitement, Lewis relied mainly on a supreme Court decision last July 3 that the Federal Communications Commission can discipline a radio station that broadcasts, in daytime hours, words describing sexual and excretory organs and activities. The FCC had held that airing such words violates a prohibition in the communications law against the broadcast of "indecent" language.

Abrams said that the decision of the court was narrow, applying only to the limitation of speech at certain hours. Moreover, he said, the courts have held that the communications law does not create a cause of action for a private citizen.