Puris are an unleavened bread often consumed in India, Bangladesh and Pakistan as a snack, breakfast or a light meal together with a filling or other side dishes.
Panipuri are related in that they are a small deep fried crepe that is hollowed and allowed to dry in a ball shape with a hole at the top.
This allows you to eat it with many fillings but typically tamarind chutney, potato chaat, chickpeas or red onions.
A Puri is prepared by rolling out a dough of flour and salt in a small circle and deep frying it in ghee or vegetable oil. While deep frying, the bread puffs up due to moisture in the dough which changes into steam which expands in all directions. When it is golden-brown in color, it is removed and may be served hot or saved for later use.