A cell or organism with a membrane-bound, structurally discrete nucleus and other well-developed subcellular compartments such as organelles. Eukaryotes include all organisms except viruses, bacteria, and cyanobacteria (blue-green algae). Compare prokaryote.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.