From The Collaborative International Dictionary of English v.0.48:

Adobe A*do"be ([.a]*d[=o]"b[asl]), n. [Sp.] 1. An unburnt brick dried in the sun; also used as an adjective, as, an adobe house, in Texas or New Mexico. [1913 Webster] 2. Earth from which unburnt bricks are made. [Western U. S.] [Webster 1913 Suppl.] 3. (Geol.) Alluvial and playa clays of desert and arid regions, differing from ordinary clays of humid regions in containing carbonates and other soluble minerals. [Webster 1913 Suppl.]

From WordNet (r) 2.0:

adobe n 1: the clay from which adobe bricks are made 2: sun-dried brick; used in hot dry climates [syn: adobe brick]

From Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "adobe": ashlar, biscuit, bisque, bowl, brick, bricks and mortar, cement, ceramic ware, ceramics, china, clayey, clayish, clinker, concrete, covering materials, crock, crockery, earthy, enamelware, ferroconcrete, firebrick, flag, flagstone, flooring, glass, gumbo, jug, lath and plaster, loamy, marly, masonry, mortar, pavement, paving, paving material, plasters, porcelain, pot, pottery, prestressed concrete, refractory, roofage, roofing, siding, soily, stone, tile, tiling, urn, vase, walling