The words "violin" and "fiddle" may refer to the same instrument, but they describe two very different appraches to music. The "violin" plays the elegant melodies and the fine harmonies of aristocratic European music, while the "fiddle" plays the lively rhythms and vocalese yelps of fold music all over the world.

Only in jazz has the same instrument functioned as both a "violin" and a "fiddle." Only jazz violinists -- or fiddlers, if you will -- have been able to combine the premeditated eloquence of classical music with the spontaneous rhythms and tones of folk music.

Jazz violin enjoyed a most creative period just before World War II when Ray Nance, Stephane Grappelli, Stuff Smith and Joe Venuti flourished. After the war, though, there was a fallow period until, in the '70s, a new generation of jazz violinists emerged. Now the once-neglected genre is bursting at the seams.

Out of the jazz-rock field have come such fiddlers as Mahavishnu's Jerry Goodman, Jean-Luc Ponty, Noel Pointer and Michael Urbaniak. Integrating classical Indian violin into jazz have been L. Shankar and L. Subramaniam. Coming out of the country-jazz tradition have been such fiddlers as Darol Anger, Richard Greene, Jim Buchanan, Denise Carlson and Mike Stein.

From the avant-garde end of the spectrum have come Leroy Jenkins, The String Trio of New York's Billy Bang, the Decoding Society's Akbar Ali and Malcolm Goldstein, coordinator of last week's excellent tribute to Martin Luther King Jr. Representing the mainstream tradition of Ray Nance has been John Blake; representing the gypsy jazz heritage of Stephane Grappelli has been Didier Lockwood.

The best new album by a jazz violinist is Billy Bang's "The Fire From Within" (Soul Note SN 1086). Bang proves a remarkable composer who can incorporate the aggressive rhythms and voicings of the "fiddle" into the focused structures of the "violin." His own playing ranges from quiet lyricism to sassy strutting.

Bang leads an unusual sextet of obscure but gifted young musicians. The strings of his violin are matched by Oscar Sandees' guitar; the wood sound of William Parker's bass is matched by Thurman Barker's marimba. Ahmed Abdullah's hard-edge trumpet and John Betsch's ringing drums offer a welcome contrast to the softer sounds of the other four.

Bang titled the album after a book by the mystical anthropologist Carlos Castaneda, and he named the seven tunes after chapters from the book. Whatever one thinks of Castaneda, Bang's affection for this source material gives each piece an important unemotional underpining. One can hear in the music a struggle to reach beyond the obvious for something new.

The band ranges across an impressive array of styles. The high-pitched tandem of violin and trumpet lead the fiery gypsy swing of "The Glow of Awareness." "The Nagual Julian" parlays African rhythms into a hypnotic cyclical pattern, while "The Shift Below" is a ballad held taut by the tension of Bang's nervous notes.

"The Mold of Man" is a boisterous piece that finds fiddle and trumpet lines ricocheting in all directions, while "Inorganic Beings" is the most avant-garde offering: an impatient chase that sweeps up the most eccentric harmonies. The 10-minute "New Seers" is the most impressive cut, quietly, patiently building full, rich harmonies from the understated elements of plucked strings and resonating marimba bars.

Violinist John Blake, who appears at Blues Alley tomorrow, makes a move toward pop-jazz on his new album, "Twinkling of an Eye" (Gramavision 18-8501-1). While this record delivers a number of pleasurable moments, it falls far short of Blake's stunning debut album, 1984's "Maiden Dance." On his new record the rhythm section is less flexible and the violinist gives in more easily to showy passages.

Nonetheless Blake is still a gifted instrumentalist, possessing a big tone that he sustains over long, dramatic phrases. He often makes quick, slashing moves through chord changes, only to pull up short on a hovering phrase without slipping at all. Blake is at his best on the album's title cut, a seven-minute up-tempo piece that showcases his bravura moves.

Blake's sweet tone is appropriate for the Latin feel of "La Verdad," and his violin plays off the piano imaginatively on the bluesy "Dat Dere." Too often, though, the band becomes a faceless background for Blake's solos. Each side of the album ends with a cliche'd pop-jazz piece with vocals that only reinforce the blandness of the rhythm arrangement.

French fiddler Didlier Lockwood is the kind of cult figure at home who inspires graffiti on Parisian walls. Following compatriots Stephane Grappelli and Jean-Luc Ponty, Lockwood has created a style that bridges gypsy folk roots and European art-rock. At his best, Lockwood infuses his music with a romanticism without sentimentality.

His new album, "Out of the Blue" (Gramavision 18-8504-1), teams Lockwood with an all-American rhythm section. In contrast to Lockwood's European records, where he refines his own distinctive voice, this album is devoted to the two sides feeling each other out and showing what they can do, and the sparks fly. Bassist Cecil McBee and drummer Billy Hart are two of the most melodic rhythmists in jazz, and Gordon Beck is a major revelation as a Kenny Barron-type player and composer. Pushed hard by the aggressive bassist and drummer, Lockwood extends himself to his limits with darting and swooping lines against Beck's rich harmonic backdrop.