plural meaning
EN
[ˈplʊə.ɹəl] [ˈplɔː.ɹəl] 
US WPlural
- The plural, in many languages, is one of the values of the grammatical category of number.
- Words of other types, such as verbs, adjectives and pronouns, also frequently have distinct plural forms, which are used in agreement with the number of their associated nouns.
- Some languages also have a dual (denoting exactly two of something) or other systems of number categories.
FR plural 
- NounPLplurals
- AdjectiveCOMmore pluralSUPmost plural
- Consisting of or containing more than one of something.
- (comparable) Pluralistic.
- Although the nation was far more plural than Canada in the number of its Christian groups
- Consisting of or containing more than one of something.
- More Examples
- Used in the Middle of Sentence
- Banana” has three a’s and one b. (apostrophe "s" used so that the plural of “a” is not confused with the word “as”)
- "Are" is the third-person plural of the verb "to be".
- Used in the Middle of Sentence
Definition of plural in English Dictionary
- Part-of-Speech Hierarchy
- Adjectives
- Nouns
- Countable nouns
- Countable nouns
- Adjectives
Source: Wiktionary
Grammatically, this word "plural" is an adjective. It's also a noun, more specifically, a countable noun.