lowland vs steppe

lowland

noun
  • An area which is considered particularly low or lower than surrounding areas. 

steppe

noun
  • A vast, cold, dry grass-plain. 

  • The grasslands of Eastern Europe and Asia. Similar to (North American) prairie and (African) savanna. 

How often have the words lowland and steppe occurred in a corpus of books? (source: Google Ngram Viewer )