JHO stands for a junior house officer. You gain this title if you have successfully completed one year of internship.
After a further year of residency, you become a senior house officer – or SHO.
Following one more year of residency you become a PHO – a principal house officer.
The title of PHO signifies that you are on the same level as a registrar. You will also be able to begin study in a particular medical specialty. When your specialty training begins, you officially become a registrar.