OHZ

OHZ or Ohz refer to:
 * Optimistic habitable zone, see Habitable zone for complex life
 * Original Heidelberger Zylinder, printing press from  Heidelberger Druckmaschinen
 * OHZ, common abbreviation for district Osterholz (and town Osterholz-Scharmbeck), Lower Saxony, Germany; in particular the first part of the regional license plate number, also in designations with a corresponding reference to district or town