Answer:
The Romans called the lower class people "plebians". This class consisted of working class common people who enjoyed proper citizen rights, to the slaves who were denied even the basic human rights. The Grecians on the the other hand considered the "freed people", the people who once were slaves but bought their freedom as lower class.
The lower class Grecian people were able to enjoy the basic human rights, but were never granted citizenship or any citizen rights no matter their economic status.
The lower class of Romans were further divided into 5 sub-categories, Commoners, Latins, Foreigners, Freed People and Slaves. The commoners were given proper citizen rights and were considered as free citizens of Rome. The others were given limited rights but were considered as Roman citizens except for the slaves.