Often students ask me what type of Yoga I teach.  My usual response is a mixture of Sivananda and Integral Yoga or Yoga Life Society style.  When their eyes cross in non-comprehension, I then say, "Hatha."  Ah, then their eyes return to normal and I can tell they understand.  But do they really?  In America, Hatha means to many, a type of physical Yoga that uses breathing and is not "flow" Yoga.  

Yet, I have come to understand Hatha as a part of the Six Branches of Yoga.   Bhakti, Raja, Karma, Hatha and Japa.  Yogaville's website has a wonderful explanation:
http://www.yogaville.org/integral-yoga/about-integral-yoga/

HATHA YOGA actually is more than the asanas, relaxation & breathing.  There are also kriyas, or cleansing practices that strengthen the body and mind.  Here's my latest video on this subject.  Let me know if you end up trying it.  Or maybe you already do and have a story about it.  I'd love to hear it!