Plethos

Plethos is a Greek noun meaning fullness, abundance, or a large crowd. In classical usage, it described quantity and mass, often in reference to a crowd or to the idea of a great amount. The term has given rise to a family of English words and linguistic roots that convey the sense of fullness or excess, though the standalone Greek word is primarily encountered in scholarly contexts rather than in everyday use.

Etymology and usage. Plethos derives from the Greek plēthos (πλῆθος), related to notions of fullness and multitude. In English, the root appears in words such as plethora, which denotes an excessive amount, and in technical terms like plethysm and plethysmography, which refer to swelling or changes in volume. These derivatives retain the core sense of fullness or abundance found in the original Greek.

Related concepts and distinctions. Plethos is distinct from pleonasm, another Greek-derived term used in rhetoric to indicate redundancy or superfluity; pleonasm comes from pleon, meaning “more.” While plethos centers on the idea of fullness or multitude, pleonasm focuses on surplus words. In modern discourse, plethos is most often encountered in linguistic, historical, or philological discussions rather than as a term in common usage.

See also. Plethora; plethysmography; pleonasm; Greek root plēthos.