What’s the difference between ONU and ONT?

ONU (Optical Network Unit) and ONT (Optical Network Terminal) are terminal equipments. But

they are different in application level and capacity. For example, the ONU for FTTB which is installed in the corridor is with 16 ports and it can manage 16 ONT for FTTH which will go to the end user’s home directly. ONT also can be simply understood as an ONU with single port.