1. a large or excessive amount of something.
2. (medicine, archaic) a bodily condition characterized by an excess of blood and marked by turgescence and a florid complexion
With a plethora of attractions, easy-to-use transportation, and some of our country’s top museums, Washington, D.C., should be on every family’s must-travel list. (Megan Barber, The best things to do with kids in 13 U.S. cities Curbed)
Your present plethora of acquirements will soon cure itself. (Oliver Wendell Holmes, Medical Essays
"There are probably a plethora of lessons here," the creature said, "but two in particular come to mind." (Clive Barker, Sacrament
Plethora comes from a similar Greek word meaning 'fullness.' It was first used in English in the 16th century to describe a supposed medical condition marked by an excess volume of blood causing swelling and a reddish complexion. Later, the medical use of 'plethora' was extended to indicate related medical conditions (such as an excess volume of bodily fluid or the red-skinned appearance of some newborns). These days, however, 'plethora' is more often used in a general, non-medical sense, with the meaning 'excess' or 'abundance.' (Merriam-Webster)
1540s: a medical word for 'excess of body fluid,' from Late Latin plethora , from Greek plethore 'fullness,' from plethein 'be full'. Figurative meaning 'too-muchness, overfullness in any respect' is first recorded 1700. Related to plethoric. (Online Etymology Dictionary).