Machines belong to the taxon Machina or Machinata. The defining feature that sets machine organisms apart from biological organisms is a greater prevalence of mechanical, electrical, or plasma components as opposed to the chemical machines used by cellular life.
Reproduction among machina can take many forms including fabrication, replication, and synthesis.
Though the domain machina is considered non-cellular life, it differs greatly from types of non-cellular life found in dimension E137 (viruses), and is included among domains of cellular life (Eukaryota, Bacteria, Archaea) despite this critical difference. Under this classification scheme, machina makes up one of the four domains of life. The three other domains, Bacteria, Archaea, and Eukaryota are cellular and are comprised almost exclusively of chemical components.
The origins of the earliest machines is unknown, however it is widely believed that the earliest machines were fabricated by a non-mechanical entity since conditions for machine fabrication are extremely unlikely to have occurred naturally.