[noun] [U] - a very large amount of something, esp. a larger amount than you need, want or can deal withA plethora of studies have shown the importance of the pre-school years for a child's later development.There's a plethora of restrictions on who can apply for the benefits.I can't believe there's such a plethora of books about the royal family.
PLETHORA
Meaning of PLETHORA in English
Cambridge English vocab. Кембриджский английский словарь. 2012