Vanessa Rubin looks like a jazz singer. She sounds like a jazz singer. And, wonder of wonders--in this era in which the art is generally believed to have started with Louis Armstrong and ended with Ella Fitzgerald--she doesn't even mind being called a jazz singer.

But wait a minute. Here's Harry Connick Jr. He likes to call his singing "swing music." And then there's Nnenna Freelon, whom Columbia Records executive George Butler identifies as "a young Sarah Vaughan."

And how about John Pizzarelli, who works with a Nat (King) Cole-styled trio? And Dee Dee Bridgewater and Flora Purim and Billy Stritch and Cassandra Wilson. \o7 More\f7 singers with a healthy seasoning of jazz in their styles.

Says Rubin, who opens a weeklong run at Hollywood's Cinegrill on Tuesday: "It's not just about jazz. It's about roots. And it's not just in music--it's in society, period. Everything's been stretched out and gone to the extreme, and now people are coming back to basics."

Something's going on. Consider:

- The last few months have brought new recordings by dozens of jazz or jazz-oriented singers. They range, in addition to those named above, from such established names as Shirley Horn, Bobby McFerrin and Diane Schuur to the less-familiar Patricia Barber, Sue Raney, Carol Sloane, Sally Mayes and Barbara Carroll.

- Billboard's top jazz album chart has been consistently listing vocal recordings in its Top 10.

- Most of the major labels (and many of the smaller companies as well) are pushing singers who, if not directly perceived as jazz vocalists, clearly owe more to the long history of pop-associated jazz than they do to more recent developments in rock music.

RCA/BMG has Rubin and Pizzarelli; Columbia has Connick, Freelon, Cheryl Bentyne and Mary Cleere Haran; Warner/Elektra has Natalie Cole and Al Jarreau (not always acknowledged as such but a fine jazz performer); Blue Note/Capitol has McFerrin, Dianne Reeves, Lou Rawls and Holly Cole; Verve has Bridgewater and Abbey Lincoln; GRP has Schuur; Concord has Susannah McCorkle and Carol Sloane.

Waiting in the wings at Blue Note/Capitol is Rachelle Ferrell, whose first U.S. recording will be a pop outing but who is described by many industry insiders as the most impressive jazz discovery of the decade.

- The new wave of vocalists is exploring a surprisingly diverse number of styles, everything from swing to mainstream, pop and contemporary jazz. But the single factor that unites them all is a common separation from much of the rock-pop music flow of the last 30 years.