past perfect vs past perfect tense

past perfect and past perfect tense both are nouns.

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

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

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

Other synonyms of past perfect include pluperfect, pluperfect tense.

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