Prokaryotes

Part of speech: noun

Definitions

1. A category of microscopic organisms that are single-celled and do not have a nucleus or membrane-bound organelles, setting them apart from eukaryotes
2. Unicellular entities that lack a nucleus and membrane-bound structures, representing some of the simplest life forms on Earth
3. Microscopic life forms that consist of a single cell lacking a true nucleus and membrane-enclosed organelles

Etymology: "Prokaryote" is built from three Greek-derived pieces. The first, "pro-", comes from Ancient Greek "πρό" (pró), meaning "before" or "in front of." The second, "karyon," is the Greek word for "nut" or "kernel," and by extension came to mean the kernel of a cell, the nucleus. The final element, "-ote," is a suffix used in biology for an individual organism, as in "zygote" or "eukaryote." Put together, the name describes a living thing whose cell existed before a true nucleus had formed around its genetic material. The term is a modern scientific coinage. The Greek parts were assembled by biologists to label a category of cells, so no ancient Greek writer ever used the word itself. Its meaning rests on the contrast with "eukaryote," where "eu-" means "true" or "good," so a eukaryote has a true nucleus and a prokaryote does not.