(Update August 9th 2016: This site has been dead for some time. But there is a wayback machine link that lives on)
NAHIT has released its definitions.
An EMR is a record for the doctor.
An EHR is a record for the doctors. (with data ready to move)
A PHR is a record for the patient.
A HIE is the process of moving health data.
A HIO is a O that does HIE.
A RHIO is a HIO that is Regional.
Well now that that is settled, I am sure that the whole industry will stop using the terms EMR and EHR interchangeably. I am sure that no one will refer to a RHIO as an HIE.
Thank God for the government.