The Collaborative International Dictionary of English v.0.48:

Coterie \Co`te*rie"\ (k?`te-r?"; 277), n. [F., prob. from OF.
   coterie servile tenure, fr. colier cotter; of German origin.
   See 1st Cot.]
   A set or circle of persons who meet familiarly, as for
   social, literary, or other purposes; a clique. "The queen of
   your coterie." --Thackeray.
   [1913 Webster]

WordNet (r) 3.0 (2006):

coterie
    n 1: an exclusive circle of people with a common purpose [syn:
         clique, coterie, ingroup, inner circle, pack,
         camp]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "coterie":
   age group, band, battalion, bevy, body, brigade, bunch, cabal,
   cadre, camarilla, cast, cell, charmed circle, circle, clan, clique,
   closed circle, cohort, company, complement, contingent, corps,
   covey, crew, crowd, detachment, detail, division, elite,
   elite group, faction, fleet, gang, group, grouping, groupment,
   in-group, ingroup, inner circle, junta, junto, mob, movement,
   out-group, outfit, pack, party, peer group, phalanx, platoon,
   posse, regiment, ring, salon, set, squad, stable, string, team,
   tribe, troop, troupe, we-group, wing