The Collaborative International Dictionary of English v.0.48:

combo \combo\ n.
   a small band of jazz musicians.

   Syn: jazz band, jazz group.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

combo
    n 1: a small band of jazz musicians [syn: jazz band, jazz
         group, combo]

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "combo":
   Anschluss, German band, Philharmonic, addition, admixture,
   affiliation, agglomeration, aggregation, agreement, alliance,
   alloy, amalgam, amalgamation, assimilation, association, band,
   big band, blend, blending, brass, brass band, brass choir,
   brass quintet, brass section, brasses, cabal, callithumpian band,
   cartel, centralization, chamber orchestra, coalescence, coalition,
   combination, combine, commixture, composite, composition, compound,
   concert band, concoction, confection, confederacy, confederation,
   congeries, conglomeration, conjugation, conjunction, consolidation,
   conspiracy, desks, dixieland band, ecumenism, embodiment,
   encompassment, enosis, ensemble, federalization, federation,
   fusion, gamelan orchestra, group, hookup, immixture, inclusion,
   incorporation, integration, intermixture, jazz band, jug band,
   junction, junta, league, magma, marriage, meld, melding, merger,
   military band, mixture, orchestra, package, package deal, paste,
   quartet, quintet, ragtime band, rock-and-roll group, sextet,
   skiffle band, solidification, steel band, street band, string band,
   string choir, string orchestra, string quartet, strings,
   swing band, symphony, symphony orchestra, syncretism, syndication,
   syneresis, synthesis, tie-up, trio, unification, union, waits,
   wedding, woodwind, woodwind choir, woodwind quartet, woodwinds