HDO

The abbreviation HDO may refer to:

• The sum formula for semi- heavy water
• High Definition Oberhausen, the Engl. Abbreviation for the Technology Centre Oberhausen
• Hrvatski demokratski odbor, a terrorist group of exiled Croats

The abbreviation BTE designated:

• The Handbook of Oriental Studies
• With some hearing aids the BTE Hearing Aids ( Behind-the- ear hearing aids )
• The house of the German East

• Disambiguation
• Abbreviation