An ecoregion -LRB- ecological region -RRB- , sometimes called a bioregion , is an ecologically and geographically defined area smaller than a `` realm '' or `` ecozone '' .

An ecoregion -LRB- ecological region -RRB- , sometimes called a bioregion , is the next smallest ecologically and geographically defined area beneath `` realm '' or `` ecozone '' .
