Capite Censi
They were the lowest class of citizens in ancient Rome, people not of the Nobility or Middle Class.
The term in Latin refers to "those counted by the head" in the ancient Roman census. They were counted by the head, because the capite censi owned little to no property, so much that their property was not considered as having value.
It used to be synonymous with proletarii (proletariat), meaning those citizens whose property was too small to be rated for the census. Later, the proletarii were distinguished from the capital censi as having appreciable property to the value of 11,000 asses or less.