The Collaborative International Dictionary of English v.0.48:

Unicameral \U`ni*cam"e*ral\, a. [Uni- + L. camera vault.]
   Having, or consisting of, a single chamber; -- said of a
   legislative assembly. [R.] --F. Lieber.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unicameral
    adj 1: composed of one legislative body [ant: bicameral]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "unicameral":
   bicameral, congressional, deliberative, lawmaking, legislative,
   legislatorial, monadal, monadic, one-piece, one-sided,
   parliamentary, senatorial, uniangulate, unibivalent, unibranchiate,
   unicellular, unicuspid, unidentate, unidigitate, unidimensional,
   unidirectional, uniflorous, unifoliate, unifoliolate, unigenital,
   uniglobular, unilateral, unilinear, uniliteral, unilobed,
   unilobular, unimodular, unimolecular, uniocular, unipart,
   unipartite, unipolar, univalent, univocal