Ludi Saeculares vs plural form

Ludi Saeculares and plural form both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ludi Saeculares	Yes	No	No	No
plural form	Yes	No	No	No

Ludi Saeculares (noun)	plural form (noun)
the centennial rites and games of ancient Rome that marked the commencement of a new generation (100 years representing the longest life in a generation); observances may have begun as early as the 5th century BC and lasted well into the Christian era	the form of a word that is used to denote more than one