verb (v)

• mark with a grammatical morpheme that indicates plural(verb.communication)

  Example:
  How do speakers pluralize nouns in Japanese?.
  

  Synonym:
  pluralise
  

  source: wordnet30
• To make plural by using the plural termination; to attribute plurality to; to express in the plural form.(verb)

  source: webster1913
• To take a plural; to assume a plural form; as, a noun pluralizes.(verb)

  source: webster1913