American Broadcasting Cos. Inc. is considering a major diversification move outside of the broadcasting and leisure area, Chairman Leonard Goldenson told shareholders yesterday at the company's annual meeting.

Goldenson, in listing the company's priorities, said management is currently determining " whether our long-term interests can best be served by the acquisition or development of another base of operation."

The ABC chirman said that "any acquisition must have solid growth potential and proven amanagement inplace," but he was not more specific.

Discussing the company's current operations, Goldenson predicted that with the record results for the first quater already in and the rest of the year shaping up strongly, "the full year will also be exceptional in terms of sales and earnings."

ABC President Elton H Rule said network advertising has been such sold through the third quater, and that sales here began for the new season begining in the fall.

"Our prices will be higher, but the rate of increase will be down from a year ago, Rule said. "So far, advertiser reception has been excellent."

In 1977, as ABC benefitted from its leading position in the prime-time ratings and went ahead of CBS as the country's largest advertising medium, broadcasting accounted for more than 75 percent of the company's total revenues of $1.6 billion. Broadcasting also produces $273.6 million in pretax operating income.

ABC's other activities include several publishing operations, theme parks, and a record division that has posted more than $60 million in losses for the last three years. Last year it registered a $29.8 million operating loss.

But Goldenson said, "recorded music is a natural activity for any entertainment-oriented company" he added that expectations were for operations to break even by 1979.

Much of the meeting was taken up by representatives of ther Synanon organization which has filed a 42 million libel and defamation of character suit against the network for a series of broadcasts about the organizations by ABC's San Francisco television station, KGO. Goldenson declined to respond directly to their complains, because the suit is pending in court.

One shareholder complained that much of ABC's prime time schedule, while it was "doing very well" is "no mental challenge to anyone." He quoted H.L. Mencken who said "no one ever went broke underestimating the intelligence of the American people."

He said Charlie's Angels, one of ABC's most popular shows, was "very sexist" and said that the network's "bread and butter series could show a little better standards and better aspirations."

"We cannot cater to one group," Goldenson responded. "We must cater to the largest mass of people, and not just to articulate minorities."