The Collaborative International Dictionary of English v.0.48:

Steppe \Steppe\, n. [From Russ. stepe, through G. or F. steppe.]
   One of the vast plains in Southeastern Europe and in Asia,
   generally elevated, and free from wood, analogous to many of
   the prairies in Western North America. See Savanna.
   [1913 Webster]

   Steppe murrain. (Far.) See Rinderpest.
      [1913 Webster]

WordNet (r) 3.0 (2006):

steppe
    n 1: extensive plain without trees (associated with eastern
         Russia and Siberia)

Moby Thesaurus II by Grady Ward, 1.0:

145 Moby Thesaurus words for "steppe":
   Lebensraum, agricultural region, air space, alkali flat,
   alluvial plain, arable land, back country, basin, billiard table,
   black belt, bottomland, bowling green, bushveld, campo, champaign,
   champaign country, citrus belt, clear space, clearance, clearing,
   coastal plain, corn belt, cotton belt, countryside, dead flat,
   dead level, delta, desert, distant prospect, down, downs,
   dust bowl, earth, empty view, esplanade, farm belt, farm country,
   farmland, fell, flat, flat country, flatland, flats, floor,
   fruit belt, glade, grass, grass roots, grass veld, grassland,
   grazing, grazing region, ground, haugh, haughland, heath,
   highlands, homaloid, horizontal, horizontal axis, horizontal fault,
   horizontal line, horizontal parallax, horizontal plane,
   horizontal projection, lande, lea, ledge, level, level line,
   level plane, living space, llano, lowland, lowlands, lunar mare,
   mare, mead, meadow, meadow land, meadows and pastures,
   mean sea level, mesa, mesilla, moor, moorland, moors, open country,
   open space, outback, pampa, pampas, park, parterre, pasturage,
   pasture, pasture land, peneplain, plain, plains, plane, plateau,
   platform, playa, prairie, prairies, province, provinces, range,
   rural district, rustic region, salt flat, salt marsh, salt pan,
   savanna, sea level, sea of grass, sebkha, steppeland, steppes,
   swale, table, tableland, terrace, terrain, territory, the country,
   the soil, the sticks, tobacco belt, tree veld, tundra, upland,
   uplands, vega, veld, water level, weald, wheat belt,
   wide-open spaces, wilderness, wold, woodland, woods and fields,
   yokeldom