'Eukarya' originates from New Latin (via Greek), specifically the word 'eukaryon' in Greek, where 'eu-' meant 'good' or 'well' and 'karyon' meant 'kernel' or 'nucleus'.

'Eukarya' developed from the Greek 'eukaryon' and from the scientific terms 'eukaryote'/'Eukaryota'; in modern biological classification the form 'Eukarya' was adopted as the name of the domain (popularized in the three-domain system by Carl Woese and colleagues).

Initially the element referred to 'true kernel' or 'true nucleus' (distinguishing cells with a nucleus); over time it came to denote the taxonomic domain encompassing organisms with membrane-bound nuclei.