Ok... so let us break this down for ya!
This tells you everything you need to know. oGoodbye can be any object in the kotor world - a container, a person, the PC, a computer console, etc.
oGoodbye = GetObjectByTag("n_jordin");
This is defining that oGoodbye is now assigned the value of "n_jordin", which is a tag of an NPC, I am guessing.
Now we understand why the object has been given this clever name "oGoodbye". Whatever object that is assigned to oGoodbye is going to be destroyed. It is going away, goodbye.
So, it could have been called, "oLaterdude", or "oGottago" or "oImouttahere" or "oDestroyme".
Please understand, oGoodbye is referring to a data type.