Any organism composed of one or more cells, each of which contains a clearly defined nucleus enclosed by a membrane, along with organelles (small, self-contained, cellular parts that perform specific functions). The organelles include mitochondria, chloroplasts, a Golgi apparatus, an endoplasmic reticulum, and lysosomes. All organisms except bacteria and archaea are eukaryotes; bacteria and archaea are prokaryotes.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on eukaryote, visit

Seen & Heard

What made you look up eukaryote? Please tell us what you were reading, watching or discussing that led you here.

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More