Terms from the Mega Man Legends series.
The MegaMan Legends series happens far in the future of the other Mega Man series, and the technology of this timeline is superior to the other series. Because of this and that the appearance of the characters vary between human-like (like Roll Caskett), cyborg-like (Barrell Caskett) and completely mechanical (Bon Bonne), fans have difficult to differ the characters between humans or robots (mostly androids), and even a hybrids of the two (like cyborgs). As the series don't have a specific term to discerne the characters, except to the "carbons", biorobotics, biotechnology and synthetic biology could be considered the most plausible explanation to them. But how far the technology, the robots, and the humans changed in the timeline of the MegaMan Legends series is uncertain.
"Carbon" is how the people in Elysium (Heaven) refers to the artificially created humans in Terra (Earth). It's believed they are genetically and cyberneticly altered.
Digger, known in Japan as Digouter (ディグアウター), is the name given to people that excavate ruins protected by Reaverbots to gather ancient technology and Quantum Refractors. Among them, there is a rumor of a giant Refractor known as "Mother Lode", which is said to have enough energy to finish the energy crisis and make the wearer rich. Some Diggers search ruins to help people, while others only think in wealth. Some Diggers have partners known as "Spotters" that help them from outside. For instance, MegaMan Volnutt is a Digger and Roll Caskett a Spotter.
"Mother Lode" is a rumor between Diggers said to be a giant and valuable Refractor that has enough energy to finish the energy crisis and make the wearer rich. However, it's revealed in Mega Man Legends 2 that the Mother Lode is not a treasure, but "a catastrophe" as said by Yuna (inside Matilda). It's believed she refers to the Mother Unit Sera.
The function of the units in Elysium is to serve and protect the humans from Elysium and follow the Master System. In the far past known of the Mega Man Legends timeline, The Master is the only remaining human, and not many units are seen.
Bureaucratic Unit is a third class model from Elysium, MegaMan Juno being the only one known. His function is to control the carbon population in Kattelox Island. When he awakened in the first game and saw the population was far above the limit, he decided it would be easier to be "reinitiated" the island.
Mother Unit is a android with positronic brain built to watch over and manage a world, as said by Yuna near the end of Mega Man Legends 2. Sera and Yuna are the only Mother Units, with Sera assigned to the systems of Elysium while Yuna is to the systems of Terra. Yuna also mentions she has nanotechnology on her body, but it's unknown if Sera has it or not.
Purifier Unit, known in Japan as Irregular Hunter (the same Japanese name for Maverick Hunter), is a first class model from Elysium that has the function to seek out and eliminate "Aberrant Units" known in Japan as Irregulars (the same Japanese name for Maverick), units that malfunctioned and threatened the Master System. MegaMan Trigger is the only known Purifier Model. Mega Man Trigger was "reset" to a child form.
Servitor Unit is a class of android that serves a Mother Unit. In Mega Man Legends 2 there are two Servitor Units. Geetz is the Servitor Unit for Mistress Sera and Gatz is the the Servitor Unit for Mistress Yuna. Both Servitor Units have the ability to transform into large dragon-like Reaverbots.