No, it is not. It is a noun meaning an abundance, or overabundance (excessive in number).
Plethora is singular and the plural form is plethoras
There was a plethora of food on the table at Thanksgiving.
Plethora is a noun.
The noun plethora (a plethora) uses singular verb forms.The word plethora is an uncountable (mass) noun, a type of aggregate noun that refers to an unspecified but large number of elements, e.g. a plethora of choices.
Plethora is singular and the plural form is plethoras.
well that word is a adjective, so it depends.....
It is neither an adjective nor an adverb. "Plethora" is a noun. Use it like you might use the nouns "abundance" "quantity" or "excess", when what you want to convey is "huge amount" or "overabundance". I don't think it is often pluralized; have never seen that, anyway. Also rare would be its adjective form "plethoric", leading to a stretch to make the adverb "plethorically". Good for "plethora" for being one of those words that has very very few relatives in the language!
"Plethora" is a singular noun, so you say "is a plethora."
Superabundant, overstock, plethora, oversupply (when surplus is a noun) Excess, superfluent, leftover (when surplus is an adjective)
Plethora is singular and the plural form is plethoras
(Plethora means an abundant excess as a bountiful excesss such as riches.)"The Thanksgiving feast was a plethora of favorite foods of the family.""There was a plethora of costumes to choose from for the masquerade.""From the plethora of possible names for the project, he chose the most apt."
There was a plethora of food on the table at Thanksgiving.
"Is", since plethora is in singular form
Plethora is a noun.
The noun plethora (a plethora) uses singular verb forms.The word plethora is an uncountable (mass) noun, a type of aggregate noun that refers to an unspecified but large number of elements, e.g. a plethora of choices.
Plethora is singular and the plural form is plethoras.
The plethora of escapes from supposedly secure prisons embarrassed the hapless wardens. The success of his videos inspired a plethora of imitators.