What does eucaryotic mean?
Eucaryotic is an adjective used in biology to describe organisms whose cells contain a true nucleus enclosed by a membrane, along with other membrane-bound organelles such as mitochondria and, in plants, chloroplasts. All animals, plants, fungi, and protists are eucaryotic, in contrast to bacteria and archaea, which are prokaryotic and lack these internal compartments. The word derives from the Greek elements 'eu-', meaning good or true, and 'karyon', meaning kernel or nut, referring to the nucleus within the cell. While 'eucaryotic' is a historically established spelling, contemporary scientific writing overwhelmingly favours the variant 'eukaryotic', so readers will most often encounter this form in older textbooks or British-influenced sources. The term is confined to formal, technical contexts and is fundamental to discussions of cell structure, evolution, and classification.
adjectiveOf or relating to a eucaryote (more commonly spelled eukaryote): an organism whose cells contain a distinct membrane-bound nucleus and other membrane-bound organelles.
- (Biology) Of, relating to, or characteristic of eucaryotes — organisms whose cells possess a true, membrane-bound nucleus and membrane-bound organelles.
"Eucaryotic cells divide by mitosis, a process absent from bacteria and archaea."
"Mitochondria are organelles found only in eucaryotic cells."
"The textbook retained the older spelling 'eucaryotic' throughout its chapters on cell biology."
Every plant, animal, fungus, and protist you've ever seen is built from eucaryotic cells — yet for most of life's history on Earth, they didn't exist at all.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of eucaryotic
The word combines the Greek prefix 'eu-' (good, true, well) with 'karyon' (kernel, nut), a metaphor biologists adopted for the cell's nucleus, plus the adjectival suffix '-otic'. It was coined in the context of early twentieth-century cytology, when the distinction between nucleated and non-nucleated cells became central to biological classification. Cognates sharing the same Greek root include 'karyotype' and 'eukaryote' itself. The spelling with 'c' reflects an older transliteration convention that has largely given way to 'k' in modern usage.
Related word forms
How eucaryotic is actually used
'Eucaryotic' is a legitimate but now less common variant spelling; modern scientific literature strongly prefers 'eukaryotic', following the recommendation to transliterate Greek kappa as 'k'. The term belongs to formal, technical registers in biology and medicine.
Easily confused with eucaryotic
Eukaryotic is the standard modern spelling of the same word; 'eucaryotic' is an older or variant spelling using 'c' instead of 'k'.
Procaryotic (prokaryotic) describes organisms such as bacteria whose cells lack a membrane-bound nucleus, whereas eucaryotic organisms have nucleated cells.