past perfect vs pluperfect tense

past perfect and pluperfect tense both are nouns.

Word	Noun	Adjective	Verb	Adverb
past perfect	Yes	No	No	No
pluperfect tense	Yes	No	No	No

As nouns, past perfect and pluperfect tense are synonyms defined as:

past perfect and pluperfect tense: a perfective tense used to express action completed in the past

Other synonyms of past perfect include past perfect tense, pluperfect.

past perfect (noun)	pluperfect tense (noun)
a perfective tense used to express action completed in the past	a perfective tense used to express action completed in the past