HE MEANING of a "performing art" was conveyed by two who were not among the five honorees at the Kennedy Center Honors ceremony Sunday night. The two were Itzhak Perlman and Isaac Stern, who honored one of the five, Arthur Rubinstein, by playing a violin duet by Jean Marie Leclair-a treat that Mr. Stern had the courage to call "a chocolate eclair." Mr. Stern was as vigorous as ever, each note a jolt, as he and Mr. Perlman encouraged each other splendidly. But there was something in Mr. Perlman's expression especially, a serenity divorced from the skill of his playing, and at the same time a natural consequence of it, that went to the heart of the evening.

That expression, which could pass for Sublimity, would be well understood by the five who quietly observed the proceedings from the box tier. Marian Anderson, Fred Astair, George Balanchine, Richard Rodgers and Arthur Rublinstein have all spent long lives in the company of the sublime. These are not your run-of-the-mill geniuses. Each has not only mastered, but has also become, music and dance, the thing itself. When they are honored, so is art.

The surprising thing was how good and dignified a show the Kennedy Center put on-not only unlike the usual moronic television "tributes," but also hundreds of notches above its own former galas, in which the honoree played second fiddle to an institution celebrating (and shilling for) itself. On this occasion, there was almost none of that-no ooh-and-aah shots of the gowned and dinner-jacketed celebrities in the audience, no Don Rickles introducing John Travolta to sing a ballad to Balanchine. Instead, there were simply the performance and the performing arts, a sign perhaps that the Kennedy Center is learning how to do these things, as well as reaching a comfortable understanding of its role as a national cultural center.

There was also a rare coherence to the event, due in part to the fact that all the honorees are connected with music, and so the evening moved smoothly from work to work, from "If I Loved You" to the "chocolate eclair" to "Puttin' on the Ritz," without a hitch. This fluidity offered as good a definition of culture as one can find; for as opera, show tunes, blues, classical piano, tap and ballet followed one another, it occurred to no one to ask: Is this high art or popular art; It was and is art, the best we have, pure and simple, and magnificent.