Prokaryote

Prokaryotes are single-celled organisms without a nucleus; i.e. bacteria and archaea.

This word is formed from the Greek root 'karuon,' meaning 'nut,' combined with the prefix -pro meaning 'before.' The reference to the 'nut' is derived from an idealized concept of the nucleus as a nut in its shell. Prokaryotes are cells in a state (without a nucleus) characteristic of cells before the evolution of the nucleus. Cells with a nucleus are called eukaryotes. The prefix eu- means 'good' or 'true.' Hence, eukaryotes have a true nucleus.