microorganism

The word 'microorganism' is a modern scientific compound formed in the 19th century. Its first element, 'micro-', derives from the ancient Greek adjective mikros, meaning 'small'. The second element, 'organism', has a more complex journey, originating from the Greek organon, meaning 'tool' or 'instrument', which evolved in Latin to refer to bodily organs and later, in scientific Latin, to a complex living structure. The compound logic is perfectly transparent: it literally denotes a 'small living thing', created precisely to name the microscopic life forms revealed by the invention of the microscope.

Structure: micro (extremely small) + organism (living thing) - micro: From Greek mikros (small). A combining form meaning 'extremely small' or 'involving a microscope'. - organism: From Greek organon (tool, instrument) via Latin and Modern Latin organismus. A noun meaning 'an individual living thing'.