1. An abundance or excess of something: "[the pitcher's] sinker that clocks in the low nineties ... resulting in a plethora of weakly hit groundballs" (Buzz Bissinger).
2. An excess of blood in the circulatory system or in one organ or area.
[Late Latin plēthōra, from Greek, from plēthein, to be full; see pelə-1 in the Appendix of Indo-European roots.]
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